JP2025110281A - Laminate and molded body including same - Google Patents

Abstract

To provide a laminate including a resin layer comprising a thermoplastic acrylic resin and a resin layer comprising a polycarbonate resin, exhibiting good transparency, and capable of reducing occurrence of cracking, fracture, and whitening of the laminate in secondary molding over a broad temperature range, and a molded article including the same.SOLUTION: A laminate comprises a resin layer (A) and a resin layer (B), wherein the resin layer (A) is composed of a resin composition (A) containing a thermoplastic acrylic resin (a) comprising 50 wt.% or more of methyl methacrylate units, the resin layer (B) is composed of a resin composition (B) containing a polycarbonate resin (b), the thickness of the laminate is 350 μm or less, the haze in the thickness direction of the laminate is less than 2%, the tensile breaking elongation at 130°C to 160°C is 200% or more when the elongation before stretching of the laminate is set to 0%, and the haze of the region uniformly stretched at an elongation of 150% at 130°C to 160°C is less than 3%.SELECTED DRAWING: None

Description

The present invention relates to a laminate including a resin layer containing a thermoplastic acrylic resin and a resin layer containing a polycarbonate resin, and a molded body including the same.

Acrylic resins, such as polymethyl methacrylate, are used and developed in a variety of applications, taking advantage of their excellent properties, such as transparency, hardness, and weather resistance. Examples of applications of acrylic resins include decorative and protective applications in which films are laminated onto automobile interior and exterior parts, decorative and protective applications for the exterior members of electronic devices such as portable electronic devices, personal computers, and home appliances, protection of display surfaces, and weather resistance protection of the surfaces of building materials, etc. In such applications, acrylic resins are processed into a film shape and laminated on the surface of a molded body by various methods.

Since acrylic resins are relatively brittle materials, one common method for making them usable as films is to add core-shell rubber particles or elastomer components to the acrylic resins, which gives them flexibility in film form and secondary moldability during heat processing while maintaining transparency.

Other methods for using acrylic resin materials as transparent decorative and protective films include laminating a resin layer made of a polycarbonate resin, which has excellent toughness, onto a resin layer made of an acrylic resin (see, for example, Patent Documents 1 and 2). In addition to being used as a protective material for the flat surface of a display device or as a base material for such a protective material, a film material having a multilayer structure made of an acrylic resin layer and a polycarbonate resin layer (hereinafter also referred to as an acrylic/PC multilayer film) can also be used as a molding film or a base material for a molding film, which is laminated onto a curved or three-dimensional surface of a molded body such as a transparent cover of a display device using any molding method such as vacuum molding, film insert molding, in-mold injection molding, or three-dimensional lamination molding, to decorate and/or protect the entire molded body, protect the display surface, and impart properties such as optical functions (see, for example, Patent Documents 3 and 4).

JP 2002-370324 A JP 2007-326334 A Japanese Patent Application Publication No. 7-156197 JP 2009-234183 A

When a film material is applied for lamination onto a surface having a curved or three-dimensional shape, it may be necessary to go through a secondary molding process in which the film material is shaped into a shape that conforms to the surface of the molded article as necessary. However, since conventional acrylic/PC multilayer films are made by laminating two resin materials with different properties, there are problems such as the interface between the acrylic resin and the polycarbonate resin peeling off during stretching associated with secondary molding, causing the interface or the inside of the polycarbonate resin layer to become cloudy or white, and the film cracking and/or breaking. For this reason, conventional acrylic/PC multilayer films have not necessarily had sufficient performance in terms of secondary moldability, stretchability, or ability to conform to surface shapes, which are necessary for lamination onto curved or three-dimensional surfaces.

The present invention has been made in consideration of the above problems, and provides a laminate that includes a resin layer containing a thermoplastic acrylic resin and a resin layer containing a polycarbonate resin, has good transparency, improves secondary formability over a wide temperature range, and can suppress cracking, breakage, and whitening of the laminate during secondary forming, and a molded product containing the same.

One or more embodiments of the present invention relate to a laminate including a resin layer (A) and a resin layer (B), in which the resin layer (A) is made of a resin composition (A) including a thermoplastic acrylic resin (a) containing 50% by weight or more of methyl methacrylate units, the resin layer (B) is made of a resin composition (B) including a polycarbonate resin (b), the thickness of the laminate is 350 μm or less, the haze in the thickness direction of the laminate is less than 2%, and, when the elongation of the laminate before stretching is 0%, the tensile elongation at break at 130°C to 160°C is 200% or more, and the haze of the stretched portion uniformly stretched to an elongation of 150% at 130°C to 160°C is less than 3%.

One or more embodiments of the present invention include the laminate and a molded body substrate, and the laminate relates to a molded body laminated on the surface of the molded body substrate.

According to the present invention, it is possible to provide a laminate that includes a resin layer containing a thermoplastic acrylic resin and a resin layer containing a polycarbonate resin, and that has improved secondary formability over a wide temperature range and can suppress cracking, breakage, and whitening of the laminate during secondary forming, as well as a molded article that includes the same.

The inventors of the present invention have conducted extensive research to solve the above problems. As a result, they have found that in a laminate including a resin layer made of a resin composition containing a thermoplastic acrylic resin and a resin layer made of a resin composition containing a polycarbonate resin, when the thickness of the laminate is 350 μm or less, which is suitable for a molding film used to decorate and protect the surface of a molded body, by making the haze in the thickness direction less than 2%, the tensile breaking elongation when stretched at 130 to 160°C to 200% or more, and the haze of the stretched portion uniformly stretched at an elongation of 150% at 130 to 160°C to less than 3%, a laminate having high transparency and improved secondary moldability over a wide temperature range can be obtained, and cracking, breakage, and whitening of the laminate during secondary molding can be suppressed.

In this specification, when a numerical range is indicated with "-", the numerical range includes both end values (upper and lower limits). For example, a numerical range of "X to Y" is a range that includes both end values X and Y, and is the same range as "X or more and Y or less". Any number within that range and any range contained within that range are specifically disclosed. In addition, when multiple numerical ranges are described in this specification, they are considered to include numerical ranges that appropriately combine the upper and lower limits of different numerical ranges.

(Resin layer A)
The resin layer (A) is made of a resin composition (A) containing a thermoplastic acrylic resin (a) containing 50% by weight or more of methyl methacrylate units. The resin composition (A) preferably contains 50% by weight or more, more preferably 80% by weight or more of the thermoplastic acrylic resin (a). The resin composition (A) may contain no resin components other than the thermoplastic acrylic resin.

For the thermoplastic acrylic resin (a), a known thermoplastic acrylic resin containing 50% or more by weight of methyl methacrylate units can be used as appropriate. For example, from the viewpoint of hardness and moldability, when the total amount of the structural units of the thermoplastic acrylic resin (a) is taken as 100% by weight, a thermoplastic acrylic resin (a) containing 50 to 100% by weight of methyl methacrylate units and 0 to 50% by weight of other structural units is preferred, and a thermoplastic acrylic resin (a) containing 80 to 100% by weight of methyl methacrylate units and 0 to 20% by weight of other structural units is more preferred. The total amount of the methyl methacrylate units and other structural units in the thermoplastic acrylic resin (a) is 100% by weight.

Examples of other structural units include structural units derived from acrylic acid, acrylic acid derivatives, methacrylic acid, methacrylic acid derivatives, aromatic vinyl derivatives, vinyl cyanide derivatives, etc. The other structural units may include glutarimide structures, lactone ring structures, N-substituted maleimide structures, and unsubstituted maleimide structures, which will be described later. The other structural units contained in the thermoplastic acrylic resin (a) may be one type or a combination of two or more types.

Examples of acrylic acid derivatives include, but are not limited to, acrylic acid esters such as methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, isobutyl acrylate, cyclohexyl acrylate, 2-hydroxyethyl acrylate, 2-phenoxyethyl acrylate, benzyl acrylate, and glycidyl acrylate.

Methacrylic acid derivatives include, but are not limited to, methacrylic acid esters such as ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, phenyl methacrylate, benzyl methacrylate, cyclohexyl methacrylate, 2-phenoxyethyl methacrylate, and isobornyl methacrylate, as well as reactive ultraviolet absorbers such as 2-(2'-hydroxy-5'-(meth)acryloyloxyethylphenyl)-2H-benzotriazoles.

Examples of aromatic vinyl derivatives include, but are not limited to, styrene, vinyltoluene, and α-methylstyrene.

Vinyl cyanide derivatives include, but are not limited to, acrylonitrile and methacrylonitrile.

The thermoplastic acrylic resin (a) is not particularly limited, but for example, in order to improve heat resistance, rigidity, surface hardness, etc., highly syndiotactic PMMA may be used, which is a PMMA having a higher ratio of highly heat-resistant syndiotactic structures than the general radical polymerization of polymethyl methacrylate (hereinafter also referred to as PMMA) by controlling the stereoregularity of the main chain during polymerization of the thermoplastic acrylic resin. Examples of such highly syndiotactic PMMA include those described in JP 2017-048344 A, WO 2014/185508 A, WO 2014/185509 A, and WO 2023/238885 A.

As the thermoplastic acrylic resin (a), a thermoplastic acrylic resin in which a structural unit having a specific structure has been introduced by copolymerization, functional group modification, modification, etc., may be used in order to improve heat resistance, rigidity, surface hardness, etc. Examples of such specific structures include glutarimide structures as shown in JP-A-62-89705, JP-A-02-178310, and WO 2005/54311, lactone ring structures as shown in JP-A-2004-168882 and JP-A-2006-171464, glutaric anhydride structures obtained by thermal cyclization of (meth)acrylic acid units as shown in JP-A-2004-307834, maleic anhydride structures as shown in JP-A-5-119217, and N-substituted maleimide structures and unsubstituted maleimide structures as shown in WO 2009/84541. For example, the introduction of these structures into a thermoplastic acrylic resin makes the molecular chain rigid. As a result, it is expected that the effects of improved heat resistance, improved surface hardness, reduced heat shrinkage, improved chemical resistance, etc. can be expected. In this specification, (meth)acrylic acid is a general term for acrylic acid and methacrylic acid.

The method for producing the thermoplastic acrylic resin (a) is not particularly limited, and for example, known polymerization methods such as suspension polymerization, bulk polymerization, solution polymerization, and emulsion polymerization can be applied. It is also possible to apply any of known radical polymerization, living radical polymerization, anionic polymerization, and cationic polymerization methods.

The resin composition (A) may contain a rubber component in addition to the thermoplastic acrylic resin (a). The resin composition (A) is not particularly limited, but may contain, for example, 0 to 50% by weight of the rubber component, or 0 to 20% by weight. The rubber component may be graft copolymer particles, preferably graft copolymer particles having an average particle size of 20 to 250 nm. In this case, the resin composition (A) is preferably one in which the graft copolymer particles are dispersed in a hard matrix resin layer containing the thermoplastic acrylic resin (a). The resin composition (A) may also contain a plurality of graft copolymer particles having different average particle sizes and structures dispersed in the thermoplastic acrylic resin (a). Examples of resin compositions containing such a thermoplastic acrylic resin and a rubber component (e.g., graft copolymer particles with an average particle size of 20 to 250 nm) include those described in JP-B-55-27576, Japanese Patent No. 3960631, Japanese Patent No. 4291994, Japanese Patent No. 7219753, and Japanese Patent No. 7245082, but are not limited to these.

Resin composition (A) may contain other thermoplastic resins that are at least partially compatible with thermoplastic acrylic resin (a) as necessary, within the scope of the present invention. Examples of other thermoplastic resins include styrene resins, polycarbonate resins, amorphous saturated polyester resins, olefin-methacrylic acid derivative resins, olefin-acrylic acid derivative resins, polyimide resins, polylactic acid resins, and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) resins. Examples of styrene resins include styrene-acrylonitrile resins, styrene-(meth)acrylic acid resins, styrene-maleic anhydride resins, styrene-N-substituted or unsubstituted maleimide resins, styrene-acrylonitrile resins, and the like. Examples of the thermoplastic resin include tolyl-butadiene resin and styrene-acrylonitrile-acrylic ester resin. Among them, one or more thermoplastic resins selected from the group consisting of styrene-based resins, polycarbonate resins, and polyimide resins are preferred because they have excellent compatibility with the thermoplastic acrylic resin (a) and may improve the bending crack resistance, solvent resistance, chemical resistance, and low moisture absorption of the resin layer (A). The resin composition (A) is not particularly limited, but may contain, for example, 0 to 50% by weight, or 0 to 20% by weight, of other thermoplastic resins.

The resin composition (A) may also contain conventionally known additives as necessary, within the scope of the present invention. Examples of such additives include, but are not limited to, antioxidants, ultraviolet absorbers, light stabilizers, light diffusing agents, matting agents, lubricants, colorants such as pigments and dyes, fibrous fillers, antiblocking agents made of organic particles and/or inorganic particles, infrared reflectors made of metals and/or metal oxides, plasticizers, and antistatic agents. These additives can be used in any amount depending on the type of additive, within the scope of the present invention, or to enhance the effect of one embodiment of the present invention. The resin composition (A) is not particularly limited, but may contain, for example, 0 to 30 parts by weight, or 0 to 20 parts by weight of additives per 100 parts by weight of the resin component (total of the thermoplastic acrylic resin (a), the rubber component, and other thermoplastic resins).

The glass transition temperature of the resin composition (A) is not particularly limited, but may be, for example, 85 to 140°C, 90 to 135°C, or 95 to 130°C, from the viewpoint of the balance between the heat resistance and secondary formability of the laminate. In this specification, the glass transition temperature can be determined using a known method such as a differential scanning calorimeter (DSC).

(Resin layer B)
The resin layer (B) is made of a resin composition (B) containing a polycarbonate resin (b). The resin composition (B) preferably contains 50 to 99% by weight of the polycarbonate resin (b). Moreover, the resin composition (B) more preferably contains 50 to 99% by weight of the polycarbonate resin (b) and has a glass transition temperature of 140°C or less, more preferably has a glass transition temperature of 135°C or less, and even more preferably has a glass transition temperature of 130°C or less. When the glass transition temperature of the resin composition (B) is within the above-mentioned range, the tensile elongation at break of the laminate at 130°C to 160°C is 200% or more, and the haze of the stretched portion uniformly stretched at an elongation of 150% at 130°C to 160°C is easily less than 3%, and the occurrence of breakage, cracking, and whitening during stretching associated with secondary molding of the laminate is easily suppressed. The lower limit of the glass transition temperature of the resin composition (B) is not particularly limited, but when the glass transition temperature of the resin composition (A) is TgA, the lower limit is preferably [TgA-10°C] or more, [TgA-8°C] or more, or [TgA-6°C] or more, from the viewpoint of not excessively decreasing heat resistance.

It is preferable that the polycarbonate resin (b) contains 80% by weight or more of structural units consisting of a carbonate ester of a dihydric phenol compound.

Examples of dihydric phenol compounds include, but are not limited to, bis(4-hydroxyphenyl)methane (also known as bisphenol F), 2,2-bis(4-hydroxyphenyl)propane (also known as bisphenol A), 1,1-bis(4-hydroxyphenyl)cyclohexane, 9,9-bis(4-hydroxyphenyl)fluorene, hydroquinone, resorcinol, and 4,4'-dihydroxydiphenyl, as well as aromatic nucleus-substituted derivatives of these compounds with alkyl groups, aryl groups, halogen groups, and alkoxy groups.

As the polycarbonate resin (b), a bisphenol A type polycarbonate in which the dihydric phenol compound is bisphenol A can be suitably used. A polycarbonate polymerized using a dihydric phenol compound other than bisphenol A may also be used, or a polycarbonate polymerized using a combination of bisphenol A and another dihydric phenol compound may also be used.

The polycarbonate resin (b) may be a copolymer of a dihydric phenol compound with an aliphatic dihydric alcohol and/or an alicyclic dihydric alcohol. Examples of alicyclic dihydric alcohols include, but are not limited to, 2,2-bis(4-hydroxycyclohexyl)propane, isosorbide, cyclohexanediol, and cyclohexanedimethanol.

The polycarbonate resin (b) can be produced by appropriately using a known polymerization method without any restrictions. Examples of the polymerization method for the polycarbonate resin (b) include, but are not limited to, an interfacial polycondensation method and a melt transesterification method using a dihydric phenol compound and a carbonylating agent, a transesterification method between carbonate prepolymers, and a ring-opening polymerization method of a cyclic carbonate compound.

The polycarbonate resin (b) is not particularly limited, but for example, the weight average molecular weight is preferably 14,000 to 35,000, more preferably 15,000 to 32,000, and even more preferably 18,000 to 31,000. When the weight average molecular weight of the polycarbonate resin (b) is 14,000 or more, the toughness of the polycarbonate resin is high and the laminate is less likely to crack. When the weight average molecular weight of the polycarbonate resin (b) is 35,000 or less, the melt viscosity is not too high, the melt molding of the laminate is easy, the residual stress in the laminate is low, and the occurrence of cracks, warping, etc. is easily suppressed. The weight average molecular weight of the polycarbonate resin (b) can be measured, for example, by gel permeation chromatography (GPC).

The resin composition (B) may further contain a transparent thermoplastic resin (b2) in addition to the polycarbonate resin (b). The resin composition (B) may contain 1 to 50% by weight of the transparent thermoplastic resin (b2). The transparent thermoplastic resin (b2) is compatible with the polycarbonate resin (b) and has the effect of lowering the glass transition temperature of the polycarbonate resin (b) by mixing. Preferably, the transparent thermoplastic resin (b2) has the effect of lowering the glass transition temperature of the polycarbonate resin (b) while maintaining the transparency and toughness of the polycarbonate resin (b) and the affinity and adhesion with the thermoplastic acrylic resin (a) or the resin composition (A). Such resins are preferably one or more selected from the group consisting of polycarbonate resins having the above dihydric phenols as structural units (excluding those used as the main component of resin composition (B) as polycarbonate resin (b)) and having a lower glass transition temperature than polycarbonate resin (b), and amorphous polyester resins.

Examples of amorphous polyester resins include polyester resins such as polyalkylene terephthalate, polyalkylene naphthalate, polyarylate, polyhydroxyalkylene carboxylate, polyalkylene succinate, polylactic acid, polyalkylene adipate, and polycaprolactone, or modified polyesters that have these as the basic skeleton and are modified by partial introduction and/or complete substitution of other components, and in which the crystallinity is suppressed by some method or which have no crystallinity.

Preferably, the amorphous polyester resin has a basic skeleton such as polyethylene terephthalate, polytrimethylene terephthalate, polytetraethylene terephthalate, polyethylene naphthalate, or polyarylate obtained by polycondensation or addition condensation of the above-mentioned dihydric phenol compound and a divalent carboxylic acid derivative such as terephthalic acid and/or isophthalic acid. In order to suppress the crystallinity of these polyester resins, two or more different polyester resins may be used in combination, or the polyester resin may be modified by partially introducing a diol component or dicarboxylic acid component having a different structure into the polyester resin and/or completely replacing the polyester resin with these components.

A preferred example of modified polyester resin is a structure in which some or all of the terephthalic acid units and/or ethylene glycol units, which are constituent units of polyethylene terephthalate, are replaced with isophthalic acid units and/or 1,4-cyclohexanedimethanol units. Among these, modified polyesters in which the structure of polyethylene terephthalate, which has ethylene glycol units and terephthalic acid units as constituent units, is replaced by copolymerization of one or more components selected from the group consisting of 1,4-cyclohexanedimethanol and isophthalic acid, are preferred in terms of suppressing crystallinity, transparency, and excellent mechanical properties. Furthermore, modified polyesters in which the structure of polyethylene terephthalate, which has ethylene glycol units and terephthalic acid units as constituent units, is replaced by copolymerization of 1,4-cyclohexanedimethanol are particularly preferred because they are excellent in maintaining transparency and toughness when mixed with polycarbonate resin. More specifically, the transparent thermoplastic resin (b2) is preferably one or more selected from the group consisting of an amorphous polyester resin that is a polyester resin containing ethylene glycol units and terephthalic acid units as structural units and further contains one or more structural units selected from the group consisting of cyclohexanedimethanol units and isophthalic acid units, and an amorphous polyester resin that is a polyester resin containing cyclohexanedimethanol units and terephthalic acid units as structural units and may further contain one or more structural units selected from the group consisting of ethylene glycol units and isophthalic acid units.

As the resin composition (B), a commercially available resin composition containing a polycarbonate resin may also be used, and examples of such resin compositions include those having a glass transition temperature that is preferably lower than that of bisphenol A polycarbonate resin, more preferably 140°C or less, even more preferably 135°C or less, and even more preferably 130°C or less, and having transparency. More specifically, examples of such resin compositions include those having bisphenol A polycarbonate resin as the main component (50 to 99% by weight) as the polycarbonate resin (b), containing an amorphous polyester resin as the transparent thermoplastic resin (b2), and having a glass transition temperature of preferably 140°C or less, even more preferably 135°C or less, and even more preferably 130°C or less. Examples of such commercially available products include "SP3002" and "SP3012" manufactured by Sumika Polycarbonate Co., Ltd.

The resin composition (B) may contain conventionally known additives as necessary, as long as the object of the present invention is not impaired. Examples of such additives include additives similar to conventionally known additives that can be used in the resin composition (A). The additives may be the same as those in the resin composition (A), or may be different from those in the resin composition (A). The resin composition (B) is not particularly limited, but may contain, for example, 0 to 10 parts by weight, or 0 to 5 parts by weight, of additives per 100 parts by weight of the resin components (the total of the polycarbonate resin (b) and the transparent thermoplastic resin (b2)).

(Laminate)
In one or more embodiments of the present invention, the laminate includes the above-mentioned resin layer (A) and resin layer (B). In the laminate, the resin layer (A) and the resin layer (B) may be directly laminated, and may include other functional layers laminated between the resin layer (A) and the resin layer (B) as necessary, within a range that does not impair the effects of the present invention. The other functional layers may be laminated on one or both sides of the resin layer (A) and/or the resin layer (B).

The other functional layers are not particularly limited, and conventionally known ones can be widely applied. For example, a printing layer, a decorative layer, an adhesive layer, an antistatic layer, a thermoplastic resin layer, and an optical functional layer can be mentioned. The decorative layer may include a colored layer, a design layer, a surface unevenness layer, and an embossed layer. The adhesive layer may include a primer layer. The thermoplastic resin layer may include an antifouling layer, an antiglare layer, a fingerprint resistant layer, a hard coat layer, a scratch resistant layer, a gas barrier layer, and a gas absorption layer. The optical functional layer may include an antireflection layer (a low refractive index layer, a high refractive index layer, an ultraviolet shielding layer, an infrared shielding layer, etc.), a light diffusion layer, an antiglare layer, a matte layer, a phase difference adjustment layer, a viewing angle adjustment layer, and a polarizing layer. The laminate may include two or more types of other functional layers in combination. Also, one functional layer may have two or more functions. The other functional layer may be one or more selected from the group consisting of a hard coat layer, an anti-reflection layer, an anti-glare layer, an anti-fouling layer, an antistatic layer, a conductive layer, an adhesive layer, a printing layer, and a decorative layer.

The thickness of the laminate is 350 μm or less, preferably 30 to 350 μm, more preferably 50 to 300 μm, and even more preferably 75 to 250 μm. When the thickness of the laminate is 350 μm or less, it is easy to produce and manage it as a film roll, and the time required for heating during secondary molding can be shortened, and uniform and smooth molding can be easily performed, improving secondary moldability and reducing costs. When the thickness of the laminate is 30 μm or more, it is easy to prepare the laminate and the laminate is less likely to break.

When the laminate contains other functional layers, the thickness of the other functional layers is not particularly limited as long as they can exhibit the intended functionality, but may be, for example, 0.1 to 15 μm or 0.5 to 10 μm.

The thickness ratio of the resin layer (A) to the resin layer (B) (resin layer (A)/resin layer (B)) is preferably 97/3 to 5/95, more preferably 90/10 to 10/90, even more preferably 20/80 to 80/20, and even more preferably 30/70 to 80/20. When the thickness ratio of the resin layer (A) is 5% or more, the physical properties such as weather resistance, surface hardness, and low retardation, which are characteristics of thermoplastic acrylic resins, tend to be exhibited. When the thickness ratio of the resin layer (B) is 3% or more, the toughness, which is a characteristic of polycarbonate resins, tends to be exhibited, and it becomes easy to impart crack resistance to the laminate.

The laminate has a haze in the thickness direction of less than 2.0%. This improves transparency. The haze in the thickness direction of the laminate is preferably 1.5% or less, more preferably 1.0% or less, even more preferably 0.8% or less, even more preferably 0.6% or less, even more preferably 0.4% or less, and particularly preferably 0.3% or less. However, this does not apply when a matting agent, anti-glare agent, colorant, filler, etc. is blended into the resin layer (A) and/or the resin layer (B) depending on the application of the laminate, or when processing such as unevenness, pattern, printed decoration, etc. is performed on the surface or interface, and the appearance and haze characteristics can be made according to the application. In this specification, the haze can be measured by the method described in the examples.

From the viewpoint of transparency, the laminate preferably has a total light transmittance of 90.0% or more, and more preferably 91.0% or more. However, this does not apply when a matting agent, an anti-glare agent, a colorant, a filler, etc. is blended into the resin layer (A) and/or the resin layer (B) depending on the application of the laminate, or when the surface or interface is subjected to processing such as unevenness, a pattern, or printed decoration. In this specification, the total light transmittance can be measured by the method described in the examples.

The laminate has a tensile breaking elongation of 200% or more at 130°C to 160°C, and the haze of the stretched portion uniformly stretched to 150% elongation at 130°C to 160°C is less than 3%, assuming that the elongation of the laminate before stretching is 0%. This improves secondary formability over a wide temperature range, provides excellent formability into curved and three-dimensional shapes, and suppresses the occurrence of breakage, cracking, and whitening during stretching associated with secondary molding of the laminate. The laminate has improved secondary formability over a wide temperature range, and when the elongation of the laminate before stretching is 0%, the haze of the stretched portion uniformly stretched to 150% elongation at 130°C to 160°C is preferably 2.8% or less, more preferably 2.5% or less, and even more preferably 2.3% or less. In this specification, the tensile breaking elongation at a specified temperature and the haze of the stretched portion uniformly stretched to a specified elongation at a specified temperature can be measured by the method described in the Examples.

From the viewpoint of improving secondary formability over a wide temperature range, when the elongation of the laminate before stretching is taken as 0%, the haze of the stretched portion uniformly stretched to an elongation of 200% at 140°C to 160°C is preferably less than 3%, more preferably 2.8% or less, even more preferably 2.5% or less, even more preferably 2.3% or less, and even more preferably 2.1% or less.

A known method can be used for laminating the resin layer (A) and the resin layer (B). For example, the resin layer (A) and the resin layer (B) are laminated into a film by a co-extrusion method, the resin layer (A) and the resin layer (B) are individually molded into a film, and then, as necessary, are appropriately printed and decorated, and unevenly shaped, and then laminated using a bonding method such as adhesion and/or heat fusion, and a coating method in which the resin composition (A) is dissolved in a solvent and then coated on the surface of the resin layer (B) molded into a film to form the resin layer (A), or the resin composition (B) is dissolved in a solvent and then coated on the surface of the resin layer (A) molded into a film to form the resin layer (B), and the like. Among these, the co-extrusion method, which is a melt processing method that does not use a solvent, is preferred in terms of productivity, control of the thickness of the laminate, environmental load, and cost.

In the co-extrusion method, resin composition (A) and resin composition (B) are extruded using separate extruders, resin composition (A) and resin composition (B) are brought into a molten state, and resin composition (A) and resin composition (B) are laminated using a known method such as a feed block method or a multi-manifold method. The laminate is then introduced into a film-forming die such as a T-die to form a film, and is cooled while being brought into contact with a polishing roll, a cooling roll, and/or a cooling belt, etc., as appropriate, to form a surface shape, thereby obtaining a film-like laminate.

The laminate can be used as a decorative protective film that decorates and/or protects a molded body. The laminate may have a smooth surface, or may have any surface shape such as hairlines, prisms, uneven shapes, three-dimensional decoration, matte surfaces, rough surfaces with a certain degree of surface roughness, knurling on the film edge, etc., on one or both sides of the film-like laminate, as required for the application, within a range that does not impair the effects of the present invention. Such surface shapes can be imparted by known methods. For example, a method can be used in which the film-like laminate immediately after extrusion, or both sides of a molded film-like laminate unwound from a winding device are sandwiched between two rolls or belts having a surface shape on at least one surface, thereby transferring the surface shape of the roll.

(Molded body)
In one or more embodiments of the present invention, the molded body includes the laminate of one or more embodiments of the present invention described above, and the laminate is laminated on the surface of the molded body substrate. The laminate has a tensile elongation at break of 200% or more at 130 ° C. to 160 ° C., and the haze of the stretched portion uniformly stretched at 150% elongation at 130 ° C. to 160 ° C. is less than 3%, so that at least a part of the molded body substrate having a non-flat curved shape or a three-dimensional shape can be covered with the laminate, and a resin molded body having a three-dimensional shape can be suitably obtained. Furthermore, even in the surface coating application of a molded body substrate having at least a part of a deep-drawn shape that requires a high elongation rate, it can be preferably used without causing whitening or cracking of the coated portion. The laminate can protect and decorate the molded body by covering the molded body substrate in a molded body having various shapes.

The molded body substrate is not particularly limited, but a thermoplastic resin substrate can be suitably used. The thermoplastic resin substrate may be, for example, a polycarbonate resin having a bisphenol-based skeleton, a fluorene-based skeleton, or an isosorbide-based skeleton, an acrylic resin, a styrene-based resin (AS resin, ABS resin, MAS resin, styrene-maleimide-based resin, styrene-maleic anhydride resin, etc.), a saturated polyester resin, a polyvinyl chloride resin, a polyarylate resin, a PPS-based resin, a POM-based resin, a polyamide resin, a polylactic acid resin, a cellulose acylate-based resin, and a polyolefin-based resin. Among these, one or more selected from the group consisting of polycarbonate resin, acrylic resin, styrene resin, and amorphous polyolefin resin are preferred because of their excellent transparency, and polycarbonate resin and/or acrylic resin are more preferred because of their good adhesion to the laminate, with polycarbonate resin being even more preferred from the standpoints of high rigidity, high heat resistance, high impact resistance, adhesion to the laminate during film insert injection molding or in-mold injection molding, and suppression of clouding at the interface between the laminate and the resin of the molded body substrate.

The molded article can be used, for example, as vehicle interior materials such as automobile interior materials, vehicle exterior materials such as automobile exterior materials, housings and exterior members for portable electronic devices and personal computers, and exterior members for home appliances. Specifically, the molded article may include a display portion of a display device or a cover member for the display portion, or may include a sensor portion of a sensor device based on an optical, electromagnetic wave, ultrasonic, resistive film, or capacitive system, or a member that covers the sensor portion.

The method for producing the molded body is not particularly limited as long as it is a molding method that can cover at least a part of the molded body substrate, preferably a thermoplastic resin substrate, with the laminate. Using the laminate, a molded body having a laminate disposed on its surface can be produced, for example, by in-mold molding, film insert injection molding, etc. Furthermore, prior to in-mold molding or film insert injection molding, the laminate may be pre-shaped, as necessary, by a method such as vacuum molding, compressed air molding, or compression molding. Alternatively, the laminate may be heated and/or pressurized under reduced pressure to produce a resin molded body by disposing the laminate on the surface of a thermoplastic resin substrate having at least a part of a non-flat curved or three-dimensional shape, so-called three-dimensional laminate molding may be performed. Furthermore, the laminate may be heated and stretched appropriately while being laminated by hand onto the surface of the thermoplastic resin substrate to produce a resin molded body.

The present invention will be described in more detail below with reference to examples. The present invention is not limited to these examples.

The measurement and evaluation methods used in the examples and comparative examples are explained below.

(Glass Transition Temperature)
A differential scanning calorimeter (DSC) SSC-5200 manufactured by Seiko Instruments was used. The sample was heated to 200° C. at a rate of 25° C./min and then held at that temperature for 10 minutes.
After preliminary adjustment, the temperature was lowered to 50° C. at a rate of 25° C./min, and then the measurement was performed while the temperature was raised to 200° C. at a rate of 10° C./min. The differential value was calculated from the obtained DSC curve (SS
DC), and the glass transition temperature was calculated from the maximum point.

(Gloss)
The specular gloss at 60° was measured using a gloss meter VG7000 (manufactured by Nippon Denshoku Industries Co., Ltd.) in accordance with JIS Z 8741.

(Thickness)
The thickness (film thickness) of the laminate was measured with a PEACOCK dial gauge No. 25 (manufactured by Ozaki Manufacturing Co., Ltd.) The thickness ratio of each layer of the laminate was determined by observing the cross section with a microscope.

(Tensile test)
The laminate was cut into a size of 10 mm (width) x 100 mm (length) to prepare a test piece. A tensile test was performed on the test piece in a thermostatic chamber at 23±0.5°C using a Tensilon tensile tester (Shimadzu Corporation, AG-2000D) under conditions of a chuck distance of 40 mm and a tensile speed of 200 mm/min, and the upper yield stress, tensile stress at break, and tensile elongation at break in the MD direction were measured. The upper yield stress, tensile stress at break, and tensile elongation at break values are the arithmetic mean values of the three values excluding the highest and lowest values among the measurement results obtained using five test pieces.

(High temperature tensile test)
The laminate was cut into a size of 10 mm (width) x 100 mm (length) to prepare a test piece. The test piece was stretched to a predetermined elongation using a Tensilon tensile tester (Shimadzu Corporation, AG-2000D) equipped with a high-temperature bath set to a predetermined temperature, under conditions of a preheat time of 2 minutes, a chuck distance of 40 mm, and a tensile speed of 200 mm/min. According to the above-mentioned method for measuring tensile elongation at break, two test pieces were stretched to elongations of 100%, 150%, and 200% at a predetermined temperature. Note that the elongation was determined as 0% when unstretched, 100% when the chuck distance was twice (80 mm) the initial chuck distance (40 mm), 150% when it was 2.5 times (100 mm), and 200% when it was 3 times (120 mm).
(Determining the shape)
The state of the stretched portion of the test piece after stretching was judged according to the following criteria A to D, with A being acceptable.
A: No breakage. Stretching is uniform, and there is no unevenness in stretching (uneven stretching) such as partial necking or whitening.
B: No breakage. Stretching is not uniform, and there is uneven stretching in one or more places in the stretched portion.
C: One test piece breaks.
D: All test pieces break.
(Haze after stretching)
For those that were judged to have a shape of A (passed), the haze was measured at the center of the uniformly stretched portion.

(Total Light Transmittance and Haze)
The total light transmittance of the laminate, and the haze of the laminate and the laminate after stretching at a predetermined elongation were measured using a haze meter NDH4000 (manufactured by Nippon Denshoku Industries Co., Ltd.) in accordance with JIS K 7375:2008 and JIS K 7136:2000, respectively.

(Crack resistance)
At room temperature (23° C.), the laminate was folded 180° with the resin layer (A) facing inward, and the presence or absence of cracks was observed, and the crack resistance was evaluated according to the following criteria.
Good: No cracks Bad: Cracks present

(Shape of molded body after film insert injection molding)
The laminate was cut into a size of 50 mm x 100 mm (width x length). The two longitudinal sides of the cut laminate were fixed with Scotch (TM) mending tape to the movable side (opposite the injection gate side) of a test mold having a flat plate shape of 50 mm x 150 mm x 5 mm (width x length x thickness) and an injection gate at the center of the plate, which was attached to an injection molding machine ("FNX180ECOJECT" manufactured by Nissei Plastics Co., Ltd.), so that the resin layer A was on the mold side. Polycarbonate resin ("H2000" made by Mitsubishi Engineering Plastics) was injection molded here under conditions of a cylinder temperature of 260 ° C. to 300 ° C. and a mold temperature of 80 ° C. to obtain a molded body in the shape of a flat plate. The side opposite the injection gate side of the obtained molded body was observed and judged according to the following criteria.
Good: The laminate and the injected resin are well adhered to each other, and no abnormal appearance such as cloudiness due to partial melt flow of the laminate is observed at the interface between the laminate and the injected resin.
Poor: White turbidity is observed at the interface between the laminate and the injected resin.

[Raw materials used]
<Resin composition (A)>
(A-1)
Parapet HM (polymethyl methacrylate, manufactured by Kuraray Co., Ltd., 100% by weight of methyl methacrylate, glass transition temperature 119° C.), which is a thermoplastic acrylic resin (a)-1, was used as resin composition A-1.
(A-2)
Thermoplastic acrylic resin (a)-2, a glutarimide acrylic resin (imidization rate 13%, glass transition temperature 124 ° C.) obtained by the method described in Production Example 5 of WO 2022/137768 was used as resin composition A-2.
<Resin composition (B)>
(B-1)
A commercially available polycarbonate resin composition (manufactured by Sumika Polycarbonate Co., Ltd., product name "SP3002", glass transition temperature 123.5 ° C.) containing bisphenol A polycarbonate resin (b) (weight average molecular weight about 30,000) as the main component and amorphous modified polyester resin (b2) was used as resin composition B-1.
(B-2)
A commercially available bisphenol A polycarbonate resin (manufactured by Mitsubishi Engineering Plastics Corporation, product name "S2000", weight average molecular weight about 30,000, glass transition temperature 149.4°C) was used as resin composition B-2.
(B-3)
A commercially available bisphenol A polycarbonate resin (manufactured by Sumika Polycarbonate Co., Ltd., product name "TR1201A", weight average molecular weight about 13000, glass transition temperature 133.5°C) was used as resin composition B-3.

Example 1
A laminate was produced by co-extrusion using the resin composition (A) and the resin composition (B) shown in Table 1. A 300 mm wide two-type two-layer T-die (feed block type) was used as the T-die used for co-extrusion of the laminate. As the extruder on the resin composition (A) side, a 30 mmφ single screw extruder was used, and melt-kneading was performed at a cylinder set temperature of 260 to 270 ° C., while as the extruder on the resin composition (B) side, a 25 mmφ single screw extruder was used, and melt-kneading was performed at a cylinder set temperature of 260 ° C., and the molten resin composition (A) and resin composition (B) were put into the die set at a die temperature of 260 ° C., and a laminated film was extruded, and the laminated film was taken up by contacting with a cast roll set at 125 ° C., and a laminate (film roll) having a width of 250 mm, a thickness of the resin layer (A) made of the resin composition (A) of 40 μm, a thickness of the resin layer (B) made of the resin composition (B) of 160 μm, and a total thickness of the resin layer (A) and the resin layer (B) of 200 μm was obtained.

(Examples 2 to 3)
A laminate was produced by co-extrusion in the same manner as in Example 1, except that the resin layer (A) made of the resin composition (A) and the resin layer (B) made of the resin composition (B) had the thicknesses shown in Table 1 below.

(Examples 4 to 6)
A laminate was produced by co-extrusion in the same manner as in Example 1, except that the resin composition (A) shown in Table 1 below was used and the resin layer (A) made of the resin composition (A) and the resin layer (B) made of the resin composition (B) had the thicknesses shown in Table 1 below.

(Comparative Examples 1 to 4)
A laminate was produced by co-extrusion in the same manner as in Example 1, except that the resin composition (B) shown in Table 1 below was used and the resin layer (A) made of the resin composition (A) and the resin layer (B) made of the resin composition (B) had the thicknesses shown in Table 1 below.

The optical properties, tensile properties, and high-temperature tensile properties of the laminates obtained in the examples and comparative examples were measured as described above, and the results are shown in Table 1 below. In Table 1 below, "-" means not measured.

As can be seen from Table 1 above, the laminate of the embodiment has a haze in the thickness direction of less than 2%, a tensile elongation at break of 200% or more at 130°C to 160°C when the elongation before stretching is 0%, and the haze of the stretched area uniformly stretched to an elongation of 150% at 130°C to 160°C is less than 3%, good transparency, improved secondary formability over a wide temperature range, and the cracking, breakage, and whitening of the laminate during secondary forming can be suppressed.

On the other hand, the laminate of Comparative Example 1 has a tensile breaking elongation of less than 200% at 130°C and 150°C, and the haze of the stretched portion uniformly stretched at 150% elongation at 140°C and 160°C is 3% or more, and the secondary formability at 130°C to 160°C is poor. The laminates of Comparative Examples 2 and 3 have a tensile breaking elongation of less than 200% at 130°C, 140°C, and 150°C, and the secondary formability at 130°C to 160°C is poor. The laminate of Comparative Example 4 has a tensile breaking elongation of less than 200% at 130°C and 140°C, and the secondary formability at 130°C to 160°C is poor. The laminate of Comparative Example 4 also has poor crack resistance.

The present invention is not particularly limited, but may include, for example, the following embodiments:

[1] A laminate including a resin layer (A) and a resin layer (B),
The resin layer (A) is made of a resin composition (A) containing a thermoplastic acrylic resin (a) containing 50% by weight or more of a methyl methacrylate unit,
The resin layer (B) is made of a resin composition (B) containing a polycarbonate resin (b),
The thickness of the laminate is 350 μm or less,
The haze in the thickness direction of the laminate is less than 2%,
A laminate having a tensile breaking elongation of 200% or more at 130°C to 160°C when the elongation of the laminate before stretching is 0%, and a haze of a stretched portion uniformly stretched to an elongation of 150% at 130°C to 160°C is less than 3%.
[2] The laminate according to [1], wherein the polycarbonate resin (b) contains 80% by weight or more of a structural unit composed of a carbonate ester of a dihydric phenol compound.
[3] The laminate according to [1] or [2], wherein the content of the polycarbonate resin (b) in the resin composition (B) is 50 to 99% by weight.
[4] The laminate according to any one of [1] to [3], wherein the glass transition temperature of the resin composition (B) is 130° C. or lower.
[5] The laminate according to any one of [1] to [4], wherein the content of methyl methacrylate units in the thermoplastic acrylic resin (a) is 80% by weight or more.
[6] The laminate according to any one of [1] to [5], wherein the content of the thermoplastic acrylic resin (a) in the resin composition (A) is 50% by weight or more.
[7] The laminate according to [6], wherein the content of the thermoplastic acrylic resin (a) in the resin composition (A) is 80% by weight or more.
[8] The laminate according to any one of [1] to [7], wherein a thickness ratio of the resin layer (A) to the resin layer (B) (resin layer (A)/resin layer (B)) is 97/3 to 5/95.
[9] The laminate according to any one of [1] to [8], wherein the resin composition (B) further contains a transparent thermoplastic resin (b2) in addition to the polycarbonate resin (b).
[10] The laminate according to [9], wherein the transparent thermoplastic resin (b2) is at least one selected from the group consisting of polyester resins and polycarbonate resins (excluding the polycarbonate resin (b)).
[11] The laminate according to [10], wherein the transparent thermoplastic resin (b2) is an amorphous polyester resin.
[12] The laminate according to [11], wherein the transparent thermoplastic resin (b2) is one or more selected from the group consisting of: an amorphous polyester resin which is a polyester resin containing ethylene glycol units and terephthalic acid units as structural units, and further contains one or more structural units selected from the group consisting of a cyclohexanedimethanol unit, and an isophthalic acid unit; an amorphous polyester resin which contains cyclohexanedimethanol units and terephthalic acid units as structural units; and an amorphous polyester resin which is a polyester resin containing cyclohexanedimethanol units and terephthalic acid units as structural units, and further contains one or more structural units selected from the group consisting of an ethylene glycol unit, and an isophthalic acid unit.
[13] The laminate according to any one of [1] to [12], further comprising one or more functional layers selected from the group consisting of a hard coat layer, an antireflection layer, an antiglare layer, an antifouling layer, an antistatic layer, a conductive layer, an adhesive layer, a printing layer, and a decorative layer.
[14] A laminate according to any one of [1] to [13] and a molded article substrate,
The laminate is laminated on the surface of the molded article substrate.
[15] The molded body according to [14], wherein at least a part of the surface of the molded body substrate on which the laminate is laminated has a curved shape or a three-dimensional shape.
[16] The molded product according to any one of [14] to [15], comprising a display portion of a display device or a cover member for the display portion.
[17] The molded body according to any one of [14] to [16], comprising a sensor site of a sensor device based on an optical, electromagnetic wave, ultrasonic, resistive film, or capacitance system, or a member covering the sensor site.

The embodiments described above are not independent of each other, and without needing to go into excessive detail, a person skilled in the art can combine them as appropriate. Furthermore, components from different embodiments may be combined as appropriate.

Claims (17)

A laminate including a resin layer (A) and a resin layer (B),
The resin layer (A) is made of a resin composition (A) containing a thermoplastic acrylic resin (a) containing 50% by weight or more of a methyl methacrylate unit,
The resin layer (B) is made of a resin composition (B) containing a polycarbonate resin (b),
The thickness of the laminate is 350 μm or less,
The haze in the thickness direction of the laminate is less than 2%,
A laminate having a tensile breaking elongation of 200% or more at 130°C to 160°C when the elongation of the laminate before stretching is 0%, and a haze of a stretched portion uniformly stretched to an elongation of 150% at 130°C to 160°C is less than 3%. The laminate according to claim 1, wherein the polycarbonate resin (b) contains 80% by weight or more of structural units consisting of a carbonate ester of a dihydric phenol compound. The laminate according to claim 1, wherein the content of the polycarbonate resin (b) in the resin composition (B) is 50 to 99% by weight. The laminate according to claim 1, wherein the glass transition temperature of the resin composition (B) is 130°C or lower. The laminate according to claim 1, wherein the content of methyl methacrylate units in the thermoplastic acrylic resin (a) is 80% by weight or more. The laminate according to claim 1, wherein the content of the thermoplastic acrylic resin (a) in the resin composition (A) is 50% by weight or more. The laminate according to claim 6, wherein the content of the thermoplastic acrylic resin (a) in the resin composition (A) is 80% by weight or more. The laminate according to claim 1, wherein the thickness ratio of the resin layer (A) to the resin layer (B) (resin layer (A)/resin layer (B)) is 97/3 to 5/95. The laminate according to claim 1, wherein the resin composition (B) further contains a transparent thermoplastic resin (b2) in addition to the polycarbonate resin (b). The laminate according to claim 9, wherein the transparent thermoplastic resin (b2) is at least one selected from the group consisting of polyester resins and polycarbonate resins (excluding the polycarbonate resin (b)). The laminate according to claim 10, wherein the transparent thermoplastic resin (b2) is an amorphous polyester resin. The transparent thermoplastic resin (b2) is
An amorphous polyester resin containing ethylene glycol units and terephthalic acid units as structural units, further containing one or more structural units selected from the group consisting of cyclohexanedimethanol units and isophthalic acid units;
An amorphous polyester resin containing cyclohexanedimethanol units and terephthalic acid units as structural units, and
The laminate according to claim 11, which is one or more selected from the group consisting of amorphous polyester resins, which are polyester resins containing cyclohexanedimethanol units and terephthalic acid units as structural units, and further contain one or more structural units selected from the group consisting of ethylene glycol units and isophthalic acid units. The laminate according to claim 1, further comprising one or more functional layers selected from the group consisting of a hard coat layer, an anti-reflection layer, an anti-glare layer, an anti-fouling layer, an antistatic layer, a conductive layer, an adhesive layer, a printing layer, and a decorative layer. A laminate according to any one of claims 1 to 13, and a molded body substrate,
The laminate is laminated on the surface of the molded article substrate. The molded body according to claim 14, wherein at least a portion of the surface of the molded body substrate on which the laminate is laminated has a curved or three-dimensional shape. The molded article according to claim 14, comprising a display portion of a display device or a cover member for the display portion. The molded body according to claim 14, comprising a sensor portion of a sensor device based on an optical, electromagnetic, ultrasonic, resistive film, or capacitive system, or a member that covers the sensor portion.