JPH11179868A - Polyethylene terephthalate-based resin laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce variation in tone of color while transparency and weatherability are excellent by a method wherein a covering layer consisting of an acrylic resin is provided on at least one side of a base material sheet of amorphous state which comprises a polyethylene terephthalate-based resin of a specific repeating total constitutional unit in an ethylene terephthalate unit. SOLUTION: An acrylic resin constituting a covering layer is provided on at least one side of a base material sheet of amorphous state which comprises a polyethylene terephthalate-based resin of which an ethylene terephthalate unit is 80 mol.% or higher of a repeating total constitutional unit. For the acrylic resin, monopolymer of methyl methacrylate or acrylonitrile, or copolymer or the like having those as main constituents are preferable. Further, it is also preferable to provide an intermediate layer comprising polyethylene terephthalate-based resin between the base material sheet and the acrylic resin covering layer. For the laminating method, for example, a preheated acrylic resin film is laminated by presure fixing separately on the base material sheet and the intermediate layer, or on the laminate thereof after co-extrusion molding.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyethylene terephthalate resin laminate, and more particularly, to a polyethylene terephthalate resin laminate having excellent transparency and weather resistance, and particularly having a small change in color tone.

[0002]

2. Description of the Related Art Conventionally, polyethylene terephthalate resins have been used in addition to excellent mechanical properties and chemical properties.
It is attracting attention in terms of its excellent transparency, gas barrier properties, safety and hygiene properties, etc., and has been significantly extruded in various applications as films and sheets after being extruded. However, this polyethylene terephthalate-based resin is inferior in weather resistance, for example, when exposed to an outdoor environment, there is a problem that the color tone, transparency, impact resistance, and the like are deteriorated. Attempts have been made to improve the weather resistance of a polyethylene terephthalate-based resin by adding a light stabilizer or a light stabilizer thereto, but at present it cannot be said that a sufficient solution has been reached.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a polyethylene terephthalate resin laminate having excellent transparency, excellent weather resistance, and a small change in color tone, in view of the above-mentioned situation.

[0004]

The present invention has been made to achieve the above object. That is, the present invention relates to a polyethylene terephthalate system in which ethylene terephthalate units repeatedly account for 80 mol% or more of all constitutional units. The gist is a polyethylene terephthalate resin laminate in which a coating layer made of an acrylic resin is provided on at least one surface of a substantially amorphous base material sheet made of a resin.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, as a polyethylene terephthalate resin constituting a base sheet, a dicarboxylic acid unit mainly composed of terephthalic acid or an alkyl ester thereof (about 1 to 4 carbon atoms) and ethylene glycol are used. A polycondensate with a glycol unit as a main component, wherein the ethylene terephthalate unit repeatedly accounts for 80 mol% or more, preferably 91 mol% or more of all the structural units. When the ethylene terephthalate unit is less than the above range, the mechanical properties and chemical properties of the base sheet are inferior, and improvement of the weather resistance of the laminate cannot be expected.

The dicarboxylic acid units other than terephthalic acid and its alkyl ester include, for example, phthalic acid, isophthalic acid, 4,4'-diphenyldicarboxylic acid, 4,4'-diphenoxyethanedicarboxylic acid,
Aromatic dicarboxylic acids such as 4'-diphenyl ether dicarboxylic acid, 4,4'-diphenyl sulfone dicarboxylic acid, 2,6-naphthalenedicarboxylic acid, alicyclic dicarboxylic acids such as hexahydroterephthalic acid and hexahydroisophthalic acid, and malonic acid , Succinic acid, adipic acid, azelaic acid, aliphatic dicarboxylic acids such as sebacic acid, and as a glycol unit other than ethylene glycol, for example, propylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, Aliphatic glycols such as decamethylene glycol, neopentyl glycol and diethylene glycol, 1,1-cyclohexane dimethylol,
Alicyclic glycols such as 4-cyclohexane dimethylol, 4,4'-dihydroxybiphenyl, 2,2-bis (4'-hydroxyphenyl) propane, 2,2-bis (4'-β-hydroxyethoxyphenyl) propane ,
Bis (4-hydroxyphenyl) sulfone, bis (4-
aromatic glycols such as (β-hydroxyethoxyphenyl) sulfonic acid, and further one or more kinds of, for example, hydroxycarboxylic acids and alkoxycarboxylic acids such as p-hydroxybenzoic acid and p-β-hydroxyethoxybenzoic acid; Used as a copolymer component. Among them, isophthalic acid and the like are preferable as the dicarboxylic acid unit, and diethylene glycol and 1,4-cyclohexane dimethylol are preferable as the glycol unit.

The polyethylene terephthalate resin is phenol / tetrachloroethane (weight ratio 1 /
The intrinsic viscosity measured at 30 ° C. in the mixed solvent of 1) is 0.5
-1.3 dl / g is preferable, and 0.7-
Those having a range of 0.9 dl / g are particularly preferred. If the intrinsic viscosity is less than the above range, mechanical properties such as impact resistance as a substrate sheet tend to be inferior, and if the intrinsic viscosity exceeds the above range,
Production of the base sheet itself tends to be difficult.

In the present invention, for the polyethylene terephthalate resin constituting the base sheet, other resins such as polycarbonate resin, polyamide resin and polyolefin resin do not impair the effects of the present invention. It may be blended in the range, in which case the blending amount is about 30% by weight or less. Further, scrap resin generated in the resin manufacturing process or the resin molding process may be blended, and the blending amount in that case is about 50% by weight or less.

In the present invention, the thickness of the base sheet is
It is preferably in the range of 0.5 to 10 mm, and 1 to 10
It is particularly preferred to be in the range of 2 mm, more preferably in the range of 2 to 7 mm. When the thickness of the base sheet is less than the above range, mechanical properties such as rigidity and impact resistance as the base sheet tend to be inferior, and when the thickness exceeds the above range, a problem tends to occur in transparency as a laminate. Become.

In the present invention, a polyethylene terephthalate-based resin is optionally provided between the polyethylene terephthalate-based resin base sheet and an acrylic resin-coated layer described later in order to improve the adhesion between the two. An intermediate layer may be provided, and as the polyethylene terephthalate-based resin, similar to the polyethylene terephthalate-based resin constituting the base sheet, terephthalic acid or its alkyl (about 1 to 4 carbon atoms) ester is mainly used. A dicondensate of a dicarboxylic acid unit and a glycol unit containing ethylene glycol as a main component, and the proportion of the ethylene terephthalate units in all the repeating structural units is smaller than that in the base sheet, Specifically, the content is preferably 90 mol% or less. In addition, as a dicarboxylic acid unit other than terephthalic acid and its alkyl ester, and a glycol unit other than ethylene glycol, the same thing as in a base material sheet is mentioned. Further, the thickness of the intermediate layer is set to 0.1.
It is preferably in the range of 01 to 1 mm.

In the present invention, the acrylic resin constituting the coating layer provided on at least one surface of the base sheet includes, for example, acrylic acid, methacrylic acid, acrylate, methacrylate, acrylonitrile, methacrylonitrile and the like. And copolymers containing these as a main component. Specific examples thereof include polymethyl acrylate, methyl methacrylate-methyl acrylate copolymer, and methyl methacrylate-ethyl acrylate copolymer. Coalition, methyl methacrylate-ethyl methacrylate copolymer, polyacrylonitrile, acrylonitrile-methyl methacrylate copolymer, and the like, and a graft copolymer of acrylonitrile and / or methacrylic ester onto a rubbery polymer. it can. Among them, a homopolymer of methyl methacrylate or acrylonitrile, or a copolymer containing these as a main component is preferable.

In the present invention, the thickness of the coating layer made of the acrylic resin is preferably in the range of 0.01 to 0.1 mm, particularly preferably 0.02 to 0.08 mm. If the thickness of the coating layer is less than the above range, the effect of improving the weather resistance as a laminate tends to be insufficient,
On the other hand, if the above range is exceeded, the effect of improving the weather resistance reaches saturation and becomes economically disadvantageous. The acrylic resin coating layer preferably has a light transmittance at a wavelength of 350 nm of 1% or less. If the light transmittance at a wavelength of 350 nm exceeds the above range, the effect of improving the weather resistance of the laminate tends to be insufficient.

In the present invention, hindered phenol is used as the polyethylene terephthalate resin constituting the base sheet, the polyethylene terephthalate resin constituting the intermediate layer, and the acrylic resin constituting the coating layer. It does not exclude the inclusion of antioxidants such as benzotriazoles, benzophenones, benzoates, hindered amines, and cyanoacrylates. , 0.001 for each resin
Preferably, it is contained in the range of 0.1 to 10% by weight.
It is particularly preferable that the content is contained in the range of 01 to 3% by weight. Further, in the present invention, in addition to the antioxidant and the light stabilizer, a coloring agent such as a dye or a pigment, an ultraviolet ray blocking agent such as titanium oxide or carbon black, glass fiber, flica, mica, carbon fiber, and titanium. Fillers such as silica, clay, calcium carbonate, calcium sulfate, and glass beads, additives such as inorganic and organic nucleating agents, plasticizers, flame retardants, and flame retardant assistants. It can be contained.

The production of the polyethylene terephthalate resin laminate of the present invention can be performed by a conventionally known dry lamination,
Sequential extrusion lamination, sandwich extrusion lamination, co-extrusion molding, and a combination thereof are performed, but the polyethylene terephthalate-based resin constituting the base sheet and the intermediate layer needs to be in a substantially amorphous state As the molding conditions for at least the base sheet and the intermediate layer for that purpose, it is preferable that the polyethylene terephthalate resin is dried by a conventional method, then melt-extruded with an extruder, and cooled and solidified on a roll. The extruded resin temperature at that time is usually 200 to 3
20 ° C., and the temperature of the cooling roll is preferably 0 to
It is quenched and solidified at 70 ° C, particularly preferably in the range of 10 to 50 ° C. At the time of cooling, it is preferable that the sheet is pressed against the cooling roll by a touch roll. Here, the “substantially amorphous state” means that the crystallinity obtained by X-ray analysis is 10% or less.

The specific method of laminating the base sheet, the intermediate layer and the coating layer is as follows. The base sheet is extruded under the aforementioned conditions, or the base sheet and the intermediate layer are separately extruded under the aforementioned conditions. After molding or co-extrusion molding, the base resin sheet or the laminate of the base sheet and the intermediate layer is rolled with an acrylic resin film preheated to about 100 to 200 ° C. by a hot roll or a heater. A method of forming a coating layer by press-lamination between, a base sheet,
Or when forming a laminate of the base sheet and the intermediate layer, when the temperature range of about 100 to 300 ° C. before extrusion and cooling and solidification of these sheets, the acrylic resin film is pressure-bonded and laminated between rolls There are a method of forming a coating layer, a method of coextruding a base sheet and a coating layer, or a base sheet, an intermediate layer and a coating layer, and the like.

Specific examples of the laminated structure of the polyethylene terephthalate resin laminate of the present invention include, for example, a base sheet / cover layer, a cover layer / base sheet / cover layer, a base sheet / intermediate layer / cover. Layers, coating layers / intermediate layers / substrate sheets / intermediate layers / coating layers, and the like. In the present invention, these laminates are used for the purpose of imparting other functions within a range that does not impair the effects of the invention. Other layers may be further provided on each of the layers or on the front and back surfaces.

The polyethylene terephthalate resin laminate of the present invention described above is excellent in transparency and weather resistance, but the transparency is preferably one having a haze of 5% or less, preferably 3% or less. Is particularly preferred,
Those having 2% or less are more preferred. The weather resistance is preferably such that the change in color tone after exposure for 1000 hours with a carbon arc weather meter is 10 or less as a color difference ΔE ^* _ab according to L ^* a ^* b ^* color system specified in JIS Z8730. Particularly preferred are those of 5 or less,
Those having 2 or less are more preferred.

The polyethylene terephthalate resin laminate of the present invention can be used as a molded sheet or
Conventionally known vacuum forming method, air pressure forming method, vacuum pressure forming method,
And they are formed into a desired shape by a thermoforming method such as a plug assisted molding method, and a sign board, a signboard, a window board, a green house, a partition board, a roof board,
It is suitably used for various uses such as mechanical covers, safety covers, and lighting covers.

[0019]

EXAMPLES Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to the following examples unless it exceeds the gist. Example 1 As a resin for a base sheet, a dicarboxylic acid unit was obtained from 98 mol% of terephthalic acid and 2 mol% of isophthalic acid, a glycol unit was obtained from 98 mol% of ethylene glycol and 2 mol% of diethylene glycol, and an ethylene terephthalate unit was repeatedly constituted. Polyethylene terephthalate resin occupying 96 mol% of the unit (intrinsic viscosity 0.83 dl / g)
As a resin for the intermediate layer, a dicarboxylic acid unit is obtained from 70 mol% of terephthalic acid, 30 mol% of isophthalic acid, a glycol unit is obtained from 98 mol% of ethylene glycol and 2 mol% of diethylene glycol, and ethylene terephthalate units are repeated all the constituent units. Polyethylene terephthalate resin occupying 68 mol% of the polymer (intrinsic viscosity 0.83 dl
/ G), on both sides of a 3.8 mm thick base sheet made of amorphous polyethylene terephthalate resin,
A three-layer laminate comprising an amorphous polyethylene terephthalate-based resin provided with a 0.1 mm thick intermediate layer was co-extruded. Subsequently, an acrylic resin film (manufactured by Mitsubishi Rayon Co., Ltd., “Acryprene HBS006”) having a thickness of 0.05 mm and a light transmittance of less than 1% at a wavelength of 350 nm was applied to both surfaces of the obtained three-layer laminate at 160 ° C. Was preheated by a hot roll and laminated by pressure bonding to produce a five-layer polyethylene terephthalate resin laminate. The obtained laminate was evaluated for transparency and weather resistance by the following methods, and the results are shown in Table 1.

Transparency Haze was measured according to JIS K7105. Using a weather-resistant sunshine carbon arc weather meter (“WEL-SUN-HCA-1” manufactured by Suga Test Instruments Co., Ltd.)
Tank temperature 45 ° C, back panel temperature 63 ° C, continuous irradiation,
Under the conditions of a water spray cycle of 12 minutes / 60 minutes, the change in the color tone after exposure of the laminate for 1000 hours to the color tone before exposure was determined by L ^* a ^* b specified in JIS Z8730.
^* Calculated by the color difference ΔE ^* _ab of the following formula according to the color system.

ΔE^* _ab= ｛(L^*-L^*')^Two + (A^*−
a^*')^Two + (B^*-B^*')^Two｝^1/2(Where L^*,
a^*, B^*Is L after each irradiation^*Is L^*a^*b
^*Lightness in color system, a^*, B^*Is L^*a^*b^*table
Color coordinates in a color system, L ^*', A^*', B^*'
Are each before irradiation. )

Example 2 As a resin for the intermediate layer, a dicarboxylic acid unit was 100 mol% of terephthalic acid, and a glycol unit was ethylene glycol 9
Polyethylene terephthalate resin (intrinsic viscosity 0.82 dl / g), obtained from 0 mol%, 1,4-cyclohexane dimethylol 8 mol%, and diethylene glycol 2 mol%, wherein ethylene terephthalate units repeatedly account for 90 mol% of all constitutional units. Using a 2.8 mm thick base sheet provided with a 0.1 mm thick intermediate layer on each side
Except for using the layer laminate, a five-layer polyethylene terephthalate-based resin laminate was produced in the same manner as in Example 1, and the resulting laminate was evaluated for transparency and weather resistance.
The results are shown in Table 1.

Example 3 A single-layer sheet having a thickness of 4.0 mm was prepared using the resin for the intermediate layer used in Example 2 as the resin for the base sheet, except that no intermediate layer was provided. Then, a three-layered polyethylene terephthalate-based resin laminate was produced, and the obtained laminate was evaluated for transparency and weather resistance. The results are shown in Table 1.

Comparative Example 1 A three-layer polyethylene terephthalate resin laminate was produced in the same manner as in Example 1 except that the acrylic resin coating layer was not provided. , Transparency and weather resistance were evaluated, and the results are shown in Table 1.

[0025]

[Table 1]

[0026]

According to the present invention, it is possible to provide a polyethylene terephthalate-based resin laminate having excellent transparency and excellent weather resistance, and particularly having a small change in color tone.

Claims (7)

[Claims] 1. A coating layer comprising an acrylic resin on at least one surface of a substantially amorphous substrate sheet comprising a polyethylene terephthalate resin in which ethylene terephthalate units occupy 80 mol% or more of all the constituent units. A polyethylene terephthalate-based resin laminate, which is provided. 2. A polyethylene terephthalate-based resin (provided that the ratio of ethylene terephthalate units to the total repeating units is smaller than that of the base sheet) between the polyethylene terephthalate-based resin base sheet and the acrylic resin coating layer. The polyethylene terephthalate-based resin laminate according to claim 1, wherein a substantially amorphous intermediate layer is provided. 3. The polyethylene terephthalate-based resin laminate according to claim 1, wherein the ethylene terephthalate units of the polyethylene terephthalate-based resin of the base sheet are at least 91 mol% of the total constitutional units. 4. The wavelength of the acrylic resin coating layer is 350 nm.
The polyethylene terephthalate-based resin laminate according to any one of claims 1 to 3, wherein the light transmittance of the polyethylene terephthalate-based resin laminate is 1% or less. 5. The polyethylene terephthalate resin base sheet has a thickness of 0.5 to 10 mm, and the acrylic resin coating layer has a thickness of 0.01 to 0.1 mm.
5. The polyethylene terephthalate resin laminate according to any one of items 1 to 4. 6. The method according to claim 1, wherein the haze is 5% or less.
The polyethylene terephthalate-based resin laminate according to any one of the above. 7. A carbon arc weather meter
The change in color tone after exposure for 000 hours is 1 with a color difference ΔE ^* _ab according to the L ^* a ^* b ^* color system specified in JIS Z8730.
The polyethylene terephthalate-based resin laminate according to any one of claims 1 to 6, which is 0 or less.