JP7542406B2 - Laminate, manufacturing method thereof, and soundproofing member - Google Patents

Description

The present invention relates to a laminate, a manufacturing method thereof, and a soundproofing member.

The use of composites of resin and urethane for the purpose of sound absorption and sound insulation has been investigated.
For example, Patent Document 1 discloses a sound absorbing/cushioning material used mainly as a sound absorbing/cushioning material for building interior materials and the like, for example as a wall material, in which an adhesive layer is formed on one side of a synthetic resin foam sheet having sound absorbing/cushioning properties, and a straight concave pressure distortion line is formed on the sheet.
Furthermore, Patent Document 2 discloses that in order to obtain a sound-absorbing member with excellent sound-absorbing properties in the low frequency range, the back surface of a coated porous sound-absorbing material is partially attached to a base body with an attachment area ratio of 5 to 70%, and integrated with the base body.

Japanese Patent Application Publication No. 11-210108 Japanese Patent Application Publication No. 10-8591

However, the urethane foam layer of conventional components had a skin layer or the air bubbles in the urethane foam were closed and therefore not open, meaning that they did not provide sufficient sound insulation. In addition, the surface of the component was made of a fiber sheet, thin film, etc., so the rigidity was insufficient. When the rigidity of the component is insufficient, it is difficult to maintain the shape of the component, and the shape of the component cannot be used to fix the component to the housing of the noise source.

The present invention aims to provide a laminate and soundproofing member that maintains rigidity, is lightweight, and has excellent soundproofing properties, particularly against high-frequency sounds, as well as a method for manufacturing said laminate, and the task of achieving this objective.

<1> A laminate comprising a urethane foam layer having continuous and open cells, a flow resistance of 350,000 N·s/m4 ^or less, and a density of 10 kg/ ^m3 or more, and a resin layer containing a thermosetting resin, the density being 50 kg/m3 or ^more and 200 kg/ ^m3 or less, and the modulus measured over a 10 mm width being 0.01 N· ^m2 or more.

<2> The laminate according to <1>, wherein the urethane foam layer has a thickness of 16 to 50 mm.
<3> The laminate according to <1> or <2>, having a thickness of 20 to 55 mm.
<4> The laminate according to any one of <1> to <3>, wherein the resin layer has an areal density of 0.15 to 0.50 g/ ^cm2 .
<5> The laminate according to <4>, wherein the thermosetting resin contains at least one of an unsaturated polyester resin, a vinyl ester resin, and a urethane resin.
<6> The laminate according to any one of <1> to <5>, wherein the urethane foam layer is adjacent to the resin layer.

<7> A soundproofing material using the laminate described in any one of <1> to <6>.

<8> A method for manufacturing a laminate in which a urethane slab is placed in a mold, a plate-shaped composition containing a thermosetting resin raw material and a curing agent is charged onto the urethane slab, and the resin layer containing the thermosetting resin is bonded to the urethane foam layer while being shaped by a press.

The present invention provides a laminate and soundproofing member that maintains rigidity, is lightweight, and has excellent soundproofing properties, particularly against high-frequency sounds, as well as a method for manufacturing the laminate.

<Laminate>
The laminate of the present invention comprises a urethane foam layer having continuous and open cells, a flow resistance of 350,000 N·s/m4 ^or less, and a density of 10 kg/ ^m3 or more, and a resin layer containing a thermosetting resin, having a density of 50 kg/m3 or ^more and 200 kg/ ^m3 or less, and a modulus measured over a 10 mm width of 0.01 N· ^m2 or more.
The laminate of the present invention may have layers other than the urethane foam layer and resin layer of the above-mentioned configuration, but from the viewpoint of suppressing peeling between the layers in high temperature and high humidity environments, it is preferable that the urethane foam layer is adjacent to the resin layer.
The laminate of the present invention has continuous and open cells, so that sound waves can penetrate into the pores, vibrating the pore walls and converting them into thermal energy, thereby absorbing sound. In addition, by providing a urethane foam layer with a flow resistance of 350,000 N.s/m4 or ^less and a density of 10 kg/m3 or ^more , sound waves can easily penetrate into the urethane foam layer, providing excellent soundproofing against high-frequency sounds. In addition, by providing a resin layer containing a thermosetting resin, the laminate can maintain rigidity while being lightweight, and the modulus of a 10 mm-wide laminate is 0.01 ^N.m2 or more.

(Modulus)
The modulus of the laminate is 0.01 N· ^m2 or more when measured over a width of 10 mm.
From the viewpoint of further improving the rigidity of the laminate, the modulus of the laminate having a width of 10 mm is preferably 0.02 N·m ² or more, and more preferably 0.03 N·m ² or more.
The upper limit of the modulus of the laminate is not particularly limited, but is usually preferably 0.07 N· ^m2 or less, and more preferably 0.06 N· ^m2 or less.
The modulus of the laminate can be measured by the following method.

The laminate is cut into a test piece 100 mm long and 10 mm wide. After cutting out the resin layer by grinding, the urethane may be cut with a blade, or may be cut out all at once by a water jet or the like. The end of the resin layer of the test piece is clamped and fixed with metal fittings such as clips, and the resin layer is placed on a three-point bending jig (compliant with JIS K7171 (2010)) set with a support distance of L = 105 mm, with the resin layer facing up, and a three-point bending test is performed by applying force to the surface of the resin layer of the test piece with an indenter. The rigidity can be calculated from the slope of the test force and displacement. The modulus (EI) [N mm 2 ] of the laminate can be calculated from the load (W) [N] applied by the indenter, the deflection (δ) [mm] of the test piece, and the support distance (L) [ ^mm ] according to the following formula.
EI=[(ΔW/Δδ)×L ³ ]/(48)
It should be noted that ΔW/Δδ is calculated from the initial inclination of the three-point bending test.

(density)
The laminate has a density of 50 kg/m ³ or more and 200 kg/m ³ or less.
If the density (ρL) of the laminate is less than 50 kg/ ^m3 , the rigidity of the laminate cannot be obtained. If the density (ρL) of the laminate is more than 200 kg/ ^m3 , a sufficient soundproofing effect against high frequencies cannot be obtained.
The density of the laminate is preferably 80 kg/ ^m3 or more, more preferably 110 kg/ ^m3 or more, and even more preferably 120 kg/ ^m3 or more, and is preferably 190 kg/ ^m3 or less, more preferably 180 kg/ ^m3 or less, and even more preferably 160 kg/ ^m3 or less.
The density of the laminate can be measured by a method in accordance with JIS K 7112 (1999).

(Thickness)
The thickness (TL) of the laminate is preferably 20 to 55 mm.
When the thickness of the laminate is 20 mm or more, the rigidity of the laminate can be further improved, and when the thickness is 55 mm or less, the laminate can be made lighter.
The thickness of the laminate is more preferably 25 mm or more. The thickness of the laminate is more preferably 50 mm or less, further preferably 40 mm or less, and particularly preferably 30 mm or less.

(area density)
The areal density (ρAL) of the laminate is preferably 0.17 to 0.70 g/cm ² .
When the surface density of the laminate is 0.17 g/ ^cm2 or more, the transmission loss over the entire frequency range can be increased due to the mass, and when the surface density is 0.70 g/ ^cm2 or less, the weight of the member to which the laminate is applied can be reduced.
The areal density of the laminate is more preferably 0.20 g/cm ² or more, and even more preferably 0.22 g/cm ² or more. The areal density of the laminate is more preferably 0.60 g/cm ² or less, and even more preferably 0.55 g/cm ² or less.
The surface density of the laminate can be measured using a scale after it has been processed into a predetermined shape using a punching blade or the like.

[Urethane foam layer]
The urethane foam layer has continuous and open cells, a flow resistance of 350,000 N·s/m ⁴ or less, and a density of 10 kg/m ³ or more.
When the air bubbles in the urethane foam layer are continuous and open, the urethane foam layer is likely to absorb high-frequency sounds. When the air bubbles are, for example, ellipsoidal, they may be open at one location on the ellipsoid, or may be open at multiple locations, or may be open all over. From the viewpoint of enhancing the soundproofing effect, it is preferable that the air bubbles are all open. However, when the urethane foam layer is adjacent to, for example, a resin layer, the air bubbles on the resin layer side of the urethane foam layer are usually not open.

(Flow Resistance)
The flow resistance is an index showing the difficulty of air flowing through a urethane foam layer, and if it exceeds 350,000 N·s/ ^m4 , it is not possible to achieve a soundproofing effect against high frequency sounds.
From the viewpoint of further enhancing the soundproofing effect of the laminate against high frequency sounds, the flow resistance of the urethane foam layer is preferably 300,000 N·s/ ^m4 or less, more preferably 200,000 N·s/ ^m4 or less, and even more preferably 100,000 N·s/ ^m4 or less.
The lower limit of the flow resistance of the urethane foam layer is not particularly limited, but is preferably 500 N·s/m ⁴ or more, more preferably 800 N·s/m ⁴ or more, and even more preferably 1,000 N·s/m ⁴ or more.
The flow resistance can be measured, for example, by a flow resistance measuring device manufactured by Nihon Onkyo Engineering Co., Ltd.
In the manufacture of the laminate, the flow resistance of the urethane slab used as the raw material for the urethane foam layer and the flow resistance of the urethane foam layer of the manufactured laminate usually remain the same and are equivalent to each other.

(Thickness)
The thickness of the urethane foam layer is preferably 16 to 50 mm.
When the thickness of the urethane foam layer is 16 mm or more, the soundproofing effect against high frequency sounds can be further improved, and when the thickness is 50 mm or less, the laminate can be made lighter.
The thickness of the urethane foam layer is more preferably 17 mm or more, and even more preferably 20 mm or more, and more preferably 45 mm or less, and even more preferably 40 mm or less.

(density)
The density (ρu) of the urethane foam layer is 10 kg/m ³ or more.
If the density (ρu) of the urethane foam layer is less than 10 kg/m ³ , the soundproofing effect against high frequency sounds cannot be improved. There is no particular upper limit to the density, but from the viewpoint of suppressing an increase in the mass of the laminate, it is preferably 90 kg/m ³ or less.
The density of the urethane foam layer is more preferably 17 kg/ ^m3 or more, and even more preferably 20 kg/ ^m3 or more. The density of the urethane foam layer is more preferably 85 kg/ ^m3 or less, and even more preferably 80 kg/ ^m3 or less.
The density of the urethane foam layer can be measured by a method conforming to the apparent density measuring method of JIS K7222 (2005).

(shear modulus)
The shear modulus (E) of the urethane foam layer is preferably 300,000 N/ ^m2 or less.
When the shear modulus of the urethane foam layer is 300,000 N/m2 or ^less , the soundproofing effect against high frequency sounds can be further improved. The lower limit of the shear modulus is not particularly limited, but is usually 50 N/ ^m2 or more.
The shear modulus of the urethane foam layer is more preferably 60,000 N/ ^m2 or more, and even more preferably 70,000 N/ ^m2 or more. The shear modulus of the urethane foam layer is more preferably 250,000 N/ ^m2 or less, and even more preferably 200,000 N/ ^m2 or less.
The shear modulus of elasticity of the urethane foam layer can be measured using an elasticity measuring system manufactured by Nihon Onkyo Engineering Co., Ltd., and the elasticity is measured from the vibration transmission characteristics by vibrating the sample while applying a shear force.
In addition, in producing the laminate, the shear modulus of elasticity of the urethane slab used as the raw material of the urethane foam layer and the shear modulus of elasticity of the urethane foam layer of the produced laminate usually do not change and are equivalent to each other.

(Number of cells)
The urethane foam layer preferably has a cell number of 20 to 80 cells/25 mm.
By setting the number of cells to 20 cells/25 mm or more, the soundproofing effect against high frequency sounds can be improved, and by setting the number of cells to 80 cells/25 mm or less, a decrease in rigidity can be suppressed.
The number of cells in the urethane foam layer is preferably 25 cells/25 mm or more, more preferably 30 cells/25 mm or more, and more preferably 65 cells/25 mm or less, more preferably 60 cells/25 mm or less.
The cell number of the urethane foam layer can be measured by the method described in Appendix 1 of JIS K6400-1 (2004).

(Porosity)
The porosity of the urethane foam layer is preferably 0.90 or more.
When the porosity of the urethane foam layer is 0.90 or more, the soundproofing effect against high frequency sounds can be further improved. The porosity is usually less than 1.00.
The porosity of the urethane foam layer is more preferably 0.92 or more, and further preferably 0.95 or more.
The porosity of the urethane foam layer is expressed as Φ=V _V /V _T , where V _V is the volume of the voids and V T is the bulk volume, and can be easily calculated from the true density and bulk density of the input material.
In the production of the laminate, the porosity of the urethane slab used as the raw material for the urethane foam layer is usually the same as the porosity of the urethane foam layer of the produced laminate.

(area density)
The surface density (ρAu) of the urethane foam layer is preferably 0.01 to 0.30 g/cm ² .
When the surface density of the urethane foam layer is within the above range, the sound absorbing performance can be improved.
The surface density of the urethane foam layer is more preferably 0.02 g/ ^cm2 or more, and even more preferably 0.03 g/ ^cm2 or more. The surface density of the urethane foam layer is more preferably 0.27 g/ ^cm2 or less, and even more preferably 0.25 g/ ^cm2 or less.
The surface density of the urethane foam layer can be calculated by cutting it to a fixed length and measuring it with a scale or the like.

The urethane foam may be an ether-based urethane foam or an ester-based urethane foam.
The term "ether-based urethane" refers to a urethane in which the main component of the polyol constituting the urethane (80 mol % or more of the total polyol) is a polyether polyol. The term "ester-based urethane" refers to a urethane in which the main component of the polyol constituting the urethane (80 mol % or more of the total polyol) is a polyester polyol.
From the viewpoint of water resistance and moisture resistance, the urethane foam is preferably an ether-based urethane foam. In the ether-based urethane, the polyol may contain an ester group, but the ester group content in the total polyol is preferably 20 mol% or less. The polyol may be a single polyether polyol, or a mixture of one or more polyols other than polyether polyols.

In the present invention, the urethane foam can be obtained, for example, by using water as a blowing agent in a urethane synthesis reaction, which reacts with polyisocyanate to generate carbon dioxide.
In order to obtain continuous and open cells, the urethane foam may be sufficiently expanded and then cut in the thickness direction.
To reduce the flow resistance to 350,000 N·s/ ^m4 or less, the thickness of the urethane may be increased or the number of cells may be reduced.
In order to make the density of the urethane foam 10 kg/ ^m3 or more, the amount of water added to be used in the urethane synthesis reaction may be appropriately adjusted.
In addition, a commercially available urethane foam having continuous and open cells, a flow resistance of 350,000 N·s/m ⁴ or less, and a density of 10 kg/m ³ or more may be used.

[Resin Layer]
The resin layer includes a thermosetting resin.
The laminate of the present invention has excellent rigidity due to the inclusion of a resin layer. The resin layer is preferably made of a thermosetting resin.
From the viewpoint of further improving the soundproofing effect against high frequency sounds, the resin layer may be a foamed resin layer.

(density)
The density (ρr) of the resin layer is preferably 300 to 2000 kg/ ^m3 . If the density is 300 kg/ ^m3 or more, the rigidity of the laminate can be further improved. If the density is 2000 kg/ ^m3 or less, the sound absorbing effect is less affected. From the above viewpoint, the density of the thermosetting resin is more preferably 700 to 1950 kg/ ^m3 , and further preferably 1000 to 1900 kg/ ^m3 .

(Thermosetting resin)
Examples of the thermosetting resin include unsaturated polyester resins, epoxy resins, vinyl ester resins, phenol resins, polyamide resins, urea resins, melamine resins, polyimide resins, diallyl phthalate resins, and urethane resins.
The thermosetting resin may be used alone or in combination of two or more kinds.
Among these, from the viewpoint of productivity, unsaturated polyester resins, vinyl ester resins and urethane resins are preferred, and unsaturated polyester resins are more preferred.
The thermosetting resin can be obtained by curing a composition containing a thermosetting resin raw material and a curing agent.

The unsaturated polyester resin raw material may be a known unsaturated polyester resin raw material obtained by dissolving a condensation product obtained from an unsaturated polycarboxylic acid and a polyhydric alcohol in a vinyl monomer.
Examples of the unsaturated polycarboxylic acid include maleic anhydride, fumaric acid, adipic acid, phthalic anhydride, isophthalic acid, etc. Examples of the polyhydric alcohol include ethylene glycol, 1,3-butylene glycol, diethylene glycol, propylene glycol, etc. Examples of the vinyl monomer include styrene-based monomers, etc.

Peroxides can be used as a curing agent (polymerization initiator) for the raw material of the unsaturated polyester resin.
Examples of the peroxide include organic peroxides such as benzoyl peroxide, lauroyl peroxide, methyl ethyl ketone peroxide, peroxy perbenzoate, peroxy ketal, and dicumyl peroxide. The peroxides may be used alone or in combination of two or more. A chain transfer agent may also be used.
The addition ratio of the curing agent is preferably 0.1 to 10 parts by mass, and more preferably 0.3 to 5.0 parts by mass, per 100 parts by mass of the raw material unsaturated polyester resin.

Examples of epoxy resins include bisphenol-type epoxy resins such as bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, and bisphenol S-type epoxy resins; novolac-type epoxy resins such as phenol novolac-type epoxy resins and cresol novolac-type epoxy resins; alicyclic epoxy resins; glycidyl ether-type epoxy resins; glycidylated amine-type epoxy resins; halogenated epoxy resins; and addition polymers of epoxy group-containing monomers or oligomers such as glycidylated polyesters, glycidylated polyurethanes, and glycidylated acrylics.
The epoxy resin may be used alone or in combination of two or more kinds.

Examples of the curing agent for the epoxy resin include acid anhydrides such as methylhexahydrophthalic anhydride, phenolic resins such as novolac-type phenolic resins and cresol novolac-type epoxy resins, phthalic anhydride derivatives, dicyandiamide, imidazole compounds, aluminum chelates, amine complexes of Lewis acids such as _BF3 , etc. These curing agents may be used alone or in combination of two or more kinds.

Compositions containing thermosetting resin raw materials and curing agents can contain modifiers such as foaming agents, extenders, colorants, UV absorbers, antioxidants, fire retardants, antifungal agents, plasticizers, coupling agents, electrically conductive fillers, magnetic fillers, thermally conductive fillers, antistatic agents, and elastic fine particles, as necessary.

(area density)
The surface density (ρAr) of the resin layer is preferably 0.07 to 0.60 g/cm ² .
When the surface density of the resin layer is 0.07 g/cm ² or more, rigidity can be ensured, and when the surface density is 0.50 g/cm ² or less, a lightweight laminate can be obtained.
The surface density of the resin layer is more preferably 0.16 g/cm ² or more, and even more preferably 0.17 g/cm ² or more. The surface density of the resin layer is more preferably 0.46 g/cm ² or less, and even more preferably 0.41 g/cm ² or less.
The surface density of the resin layer can be calculated by subtracting the surface density of the urethane added from the surface density of the laminate. The surface density of the laminate can be calculated by cutting the laminate to a fixed size, weighing it, and then performing the calculation.

(Thickness)
The thickness (Tr) of the resin layer is preferably 0.50 to 5.00 mm.
When the thickness of the resin layer is 0.50 mm or more, the rigidity of the laminate can be further improved, and when the thickness is 5.00 mm or less, the laminate can be made lighter.
The thickness of the resin layer is more preferably 0.85 mm or more, and even more preferably 1.10 mm or more. The thickness of the resin layer is more preferably 3.20 mm or less, and even more preferably 2.80 mm or less.

<Method of manufacturing laminate>
The method for producing the laminate of the present invention is not particularly limited as long as it is a method capable of laminating the above-mentioned urethane foam layer and resin layer. However, it is preferable that the urethane foam layer and the resin layer are not laminated via an adhesive or a pressure sensitive adhesive, and the urethane foam layer is laminated adjacent to the resin layer. By laminating the urethane foam layer adjacent to the resin layer, the urethane foam layer and the resin layer are unlikely to peel off even if the laminate is placed in a high temperature environment, a high humidity environment, or the like.
The laminate in which the urethane foam layer is laminated so as to be adjacent to the resin layer can be produced, for example, by the following method.

This manufacturing method involves placing a urethane slab in a mold, charging a plate-shaped composition containing a thermosetting resin raw material and a curing agent onto the urethane slab, and simultaneously shaping the slab with a press while bonding the resin layer containing the thermosetting resin to the urethane foam layer.

The mold is a container-like mold that fits together, and typically has a convex upper mold (core) and a concave lower mold (cavity). A spacer may be provided at the pressure receiving portion between the upper and lower molds to control the thickness of the urethane slab and plate-like composition. In addition, the upper or lower mold may be equipped with an ejector to make it easier to remove the manufactured laminate from the mold.

It is preferable to heat the upper and lower dies in advance before putting the urethane slab and the plate-shaped composition into the die. When the temperature of the die on the urethane side is Tu and the temperature of the die on the plate-shaped composition side, i.e., the side on which the resin layer is formed, is Tr, Tu and Tr may be the same, but since raising the temperature of the urethane slab too much will cause the urethane to irreversibly collapse, it is preferable that Tr>Tu.
Tr and Tu vary depending on the mass of the urethane slab and the mass of the plate-shaped composition, but for example, when the curing temperature of the resin is 120°C, Tr may be set to 120°C and Tu to 115°C.

Normally, a urethane slab is placed in the lower mold (cavity), a sheet-shaped composition is charged onto the urethane slab, and then the upper mold (core) is placed on top.

The urethane slab may be a urethane foam having continuous and open cells and a flow resistance of 350,000 N·s/ ^m4 or less, processed into a slab (block) of the desired shape. The shape of the urethane slab is usually the same as the bottom shape of the lower mold (cavity), but it may be a shape that covers part of the bottom shape of the cavity. The thickness of the urethane slab may be in the same range as the thickness of the urethane foam layer of the laminate.

The plate-shaped composition containing a thermosetting resin raw material and a curing agent refers to a so-called SMC (Sheet Molding Compound), which is an uncured thermosetting resin obtained by molding a composition containing a thermosetting resin raw material and a curing agent into a plate shape. The thermosetting resin raw material and the curing agent may be the same as those described above, and the plate-shaped composition may contain a modifier such as a foaming agent.
The shape of the plate-shaped composition (SMC) may be the same as that of the urethane slab, or may be a shape that covers a part of the urethane slab. The amount (W) of the plate-shaped composition (SMC) is calculated and determined so that the thickness after curing falls within the range of the thickness of the resin layer of the laminate.

Then, the mold is shaped by pressing. That is, the upper mold is lowered or the lower mold is raised and the mold is clamped. At this time, it is preferable to apply pressure (press pressure; P) to the urethane slab and the plate-shaped composition, crushing the plate-shaped composition to a predetermined cavity spacing (L0), and holding it in this position for a predetermined time (pressure holding time; Tp).

The cavity interval (L0) may be adjusted by controlling the position of the press, or by controlling the size of the spacer.
The press pressure (P), cavity spacing (L0), and pressure holding time (Tp) vary depending on the mass of the urethane slab and the mass and composition of the plate-shaped composition, but for example, P may be 3 to 15 MPa, L0 may be 2 to 10 mm, and Tp may be 2 to 15 minutes.

Then, the upper die is slowly raised or the lower die is slowly lowered to remove the molded product (laminate) from the mold. The molded product may be removed using an ejector or by using the end or protrusion of the molded product.

<Soundproofing materials>
The soundproofing material of the present invention is formed using the laminate of the present invention.
Therefore, the soundproofing material of the present invention maintains its rigidity and has excellent soundproofing properties against high frequency sounds.
The soundproofing material of the present invention is suitable for parts, products, etc. that require rigidity and soundproofing against high-frequency sounds. Examples of such parts include vehicle parts, building parts, etc. As an example of a vehicle part, the soundproofing material can be used for an engine cover.

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples in any way.

<Ingredients>
1. Urethane Slab A urethane slab having the properties shown in Table 1 was prepared as a material for forming a urethane foam layer. Urethane 1 to Urethane 3 in Table 1 are the following products. The properties of Urethane 1 to Urethane 3 shown in Table 1 are the values listed in the manufacturer's specifications.

Urethane 1:
Ether-based urethane foam, Bridgestone polyurethane foam "TP"
Urethane 2:
Ether-based urethane foam, Bridgestone polyurethane foam "VO"
Urethane 3:
Ether-based urethane foam, Bridgestone polyurethane foam "DO"

Urethane 4 to Urethane 5 in Table 1 are virtual urethane slabs obtained by simulation. The properties of Urethane 4 to Urethane 5 shown in Table 1 are the set values used in the simulation.
The simulation was performed using laminated structure acoustic characteristic prediction software, product name "STRATI-ARTZ", manufactured by Nihon Onkyo Engineering Co., Ltd.

2. Plate-shaped composition 70 parts by mass of matrix resin (unsaturated polyester resin, number average molecular weight: 3000), 25 parts by mass of low shrinkage agent (35% styrene monomer solution of polystyrene), 30 parts by mass of viscosity modifier (styrene monomer), 1 part by mass of curing agent (t-butyl peroxybenzoate), 0.05 parts by mass of polymerization inhibitor (parabenzoquinone), 10 parts by mass of internal mold release agent (zinc stearate), 4 parts by mass of modifier (powdered polyethylene) and 200 parts by mass of filler (heavy calcium carbonate) were kneaded to prepare a compound paste. Next, a mixture of 1 part by mass of thickener (magnesium oxide) and 4 parts by mass of resin (unsaturated polyester resin with an acid value of 0) was added as a thickener paste to prepare a molding material.
The unsaturated polyester resin (matrix resin) was obtained by esterification reaction using a combination of terephthalic acid and maleic acid as the dicarboxylic acid component and a combination of propylene glycol and neopentyl glycol as the glycol component. Next, after adding the thickener paste, glass fibers having a length of about 25 mm obtained by chopping glass roving with a cutter were added in a ratio of 20 mass% based on the total amount of the expandable preform, and a plate-shaped composition (SMC) was prepared according to a conventional method.

<Production of Laminate>
Example 1
(1) Setting of Mold Temperature A mold was used which was a container-like mold that fitted together and had a convex upper mold (core), a concave lower mold (cavity), and a spacer.

(2) Placement of urethane slab and plate-shaped composition The urethane slab (urethane 1) was cut to a size of 200 mm in length × 200 mm in width × 30 mm in thickness, and plate-shaped composition A was cut and the thickness was adjusted so that the amount put into the mold was 110.6 g.
A urethane slab was placed in the lower mold (cavity), and the plate-shaped composition A was charged onto the urethane slab.

(3) Clamping Next, the upper die was lowered and clamped so that the thickness of the urethane layer in the laminate after pressing was the value shown in Table 2. Thereafter, the upper die was slowly raised and the molded product was removed from the die. In this manner, laminate 1 of Example 1 was produced.
The laminate 1 is a two-layer structure consisting of a resin layer of unsaturated polyester resin (UP) and a urethane foam layer of urethane 1.

[Examples 2 to 4]
Except for changing the type of plate-shaped composition (SMC), the type of urethane slab, and the amount of plate-shaped composition (SMC) added to those shown in Table 2, laminates 2 to 4 of Examples 2 to 4 were produced in the same manner as in Example 1 so that the thickness of the urethane layer in the laminate after pressing would be the value shown in Table 2.
The laminate 2 is a two-layer structure consisting of a resin layer of unsaturated polyester resin (UP) and a urethane foam layer of urethane 2.
The laminate 3 is a two-layer structure consisting of a resin layer of unsaturated polyester resin (UP) and a urethane foam layer of urethane 3.
The laminate 4 is a two-layer structure consisting of a resin layer of foamed resin of unsaturated polyester resin (UP) and a urethane foam layer of urethane 2 .

[Example 5, Comparative Examples 3 to 6]
Except for changing the type of plate-shaped composition (SMC), the type of urethane slab, and the amount of plate-shaped composition (SMC) added to those shown in Table 2, laminate 5 of Example 5 and laminates 103 to 106 of Comparative Examples 3 to 6 were manufactured in the same manner as in Example 1 so that the thickness of the urethane layer in the laminate after pressing would be the value shown in Table 2.
Like Laminate 1, Laminate 5 is a two-layer structure consisting of a resin layer of unsaturated polyester resin (UP) and a urethane foam layer of urethane 1, but differs from Laminate 1 in that the resin layer is thicker.
The laminate 103 is a two-layer structure consisting of a resin layer of unsaturated polyester resin (UP) and a urethane foam layer of urethane 5.
The laminate 104 is a two-layer structure consisting of a resin layer of unsaturated polyester resin (UP) and a urethane foam layer of urethane 4.
The laminate 105 is a two-layered body consisting of a resin layer of foamed resin of unsaturated polyester resin (UP) and a urethane foam layer of urethane 1.
Laminate 106, like laminate 1, is a two-layer structure consisting of a resin layer of unsaturated polyester resin (UP) and a urethane foam layer of urethane 1, but differs from laminate 1 in that the thickness of the urethane layer is smaller.

Comparative Example 1
In Comparative Example 1, a molded article 101 was produced which had only a resin layer without a urethane foam layer.
Molded product 101 was produced under the same pressing conditions as in Example 3, except that no urethane slab was used and no spacer was used to maintain the cavity gap.
The molded product 101 is a single layer body made of a resin layer of unsaturated polyester resin (UP).

Comparative Example 2
As the molded article 102 of Comparative Example 2, a single layer body consisting of a urethane foam layer of Urethane 1 was prepared.

The thickness, areal density and density of the laminates or molded articles of the examples and comparative examples are shown in Table 2.
The areal density of the laminates of Examples 1 to 4 and the molded product of Comparative Example 1 was measured by cutting the laminate or molded product to a fixed length and then weighing it. The areal density of the laminates of the other Examples and Comparative Examples was estimated from the resin type, urethane type, and the thickness of the resin layer and urethane layer after pressing.

<Evaluation>
The soundproofing properties and rigidity of the laminates or molded articles of the Examples and Comparative Examples were confirmed by the following methods, and the results are shown in Tables 3 and 4.
It should be noted that Examples 1 to 4 and Comparative Examples 1 and 2 are actual measured values, while Example 5 and Comparative Examples 3 to 6 are hypothetical values based on simulation.

1. Soundproofing Evaluation (1) Measurement Using a Sound-Absorbing Box The laminates or molded articles of Examples 1 to 3 and 5 and Comparative Examples 1 to 6 were used as test specimens.
A sound-absorbing box measuring 500 mm x 800 mm x 700 mm in height and with one side open was placed with the opening facing up, and the speaker was placed inside the sound-absorbing box. The opening of the sound-absorbing box was then blocked with a board having a 200 mm x 200 mm opening in the center. At this time, the position of the board was adjusted so that the opening was directly above the speaker. Furthermore, the opening of the board was blocked with a test specimen, and the gap was blocked with tape. The laminate and molded product with a urethane foam layer had the urethane foam layer side facing the speaker, and the molded product 101 without a urethane foam layer had the resin layer facing the speaker.

A microphone was placed outside the sound-absorbing box, 20 cm away from the test specimen, and sound (4 kHz) was emitted from a speaker, and the intensity of the sound detected by the microphone was measured.
The sound intensity when there is no test specimen is defined as I ₀ , and the sound intensity when there is a test specimen is defined as I _S , and the sound transmission loss (sound absorbing box, 200 mm) was calculated from the following formula.
Transmission loss (sound absorption box, 200mm) = 10Log (I _S /I ₀ )

The larger the transmission loss value, the better the soundproofing properties.
The results of the transmission loss (sound absorbing box, 200 mm) of 44.0 dB or more were evaluated as ◯ (good), and the results of the transmission loss less than 44.0 dB were evaluated as × (bad). These results are shown in Table 3.

(2) Measurement Using an Acoustic Tube Using the laminate 1 of Example 1, the laminate 4 of Example 4, and the molded article 101 of Comparative Example 1 as test specimens, the normal incidence sound transmission loss was measured in accordance with ASTM E2611.
An acoustic tube (JIS A1405-1 (2007)) with a length of 495 mm and a diameter of 40 mm was used, with a speaker installed at one end of the tube and the other end blocked with the test specimen. To prevent sound leakage, any gaps were blocked with tape and clay. The laminates and molded products with a urethane foam layer had the urethane foam layer side facing the speaker, while the molded product 101 without a urethane foam layer had the resin layer facing the speaker.

A microphone was placed outside the sound tube and 10 cm away from the test specimen, and sound (5 kHz) was emitted from a speaker, and the intensity of the sound detected by the microphone was measured.
The sound intensity when there was no test specimen was defined as I ₀ , and the sound intensity when there was a test specimen was defined as I _S , and the transmission loss (sound tube, φ40 mm) was calculated from the following formula.
Transmission loss (acoustic tube, φ40mm) = 10Log (I _S /I ₀ )

The higher the transmission loss value, the better the soundproofing. Transmission loss (sound tube, φ40 mm) values of 40.0 dB or more are rated as ○ (good), and values below 40.0 dB are rated as × (bad), as shown in Table 4.

2. Mass The laminates or molded articles of the Examples and Comparative Examples were processed into a circle having a diameter of 40 mm, and the mass was measured. The results are shown in Tables 3 and 4.
The results are shown in Tables 3 and 4 as follows: a mass of 7.0 g or less is ◯ (good); a mass of more than 7.0 g and 8.0 g or less is △ (acceptable range); and a mass of more than 8.0 g is × (bad).
The masses of the laminates in Example 5 and Comparative Examples 3 to 6 were calculated based on the set values in the simulation.

3. Modulus of Laminate or Molded Article The laminates or molded articles of the Examples and Comparative Examples were cut to a width of 10 mm, and the modulus was measured by the following method.
The laminate was cut into a test piece measuring 100 mm in length and 10 mm in width. The test piece was cut out using a water jet. The end of the resin layer of the test piece was clamped and fixed with metal fittings such as clips, and the test piece was placed with the resin layer facing up on a three-point bending jig (compliant with JIS K7171 (2010)) set with a support distance of L = 105 mm, and a three-point bending test was performed by applying force to the surface of the resin layer of the test piece with an indenter. The rigidity was calculated from the slope of the test force and the displacement. The modulus (EI) [N mm 2 ] of the laminate was calculated from the load (W) [ ^N ] applied by the indenter, the deflection (δ) [mm] of the test piece, and the support distance (L) [mm] using the following formula.
EI=[(ΔW/Δδ)×L ³ ]/(48)
Incidentally, ΔW/Δδ is calculated from the initial inclination in a three-point bending test.
The moduli of the laminates of Example 5 and Comparative Examples 3 to 6 were calculated using the set values of the simulation.

4. Evaluation of Rigidity The evaluation of rigidity was carried out for the laminate and molded article having the resin layer.
Laminates 1 to 4 and molded articles 101 to 102 were given projections and recesses to fix the shapes, and the evaluation of whether the shape could be maintained by the receiving part is shown in Tables 3 and 4. In addition, the evaluation of the other laminates was inferred from the test results of laminates 1 to 4 and molded articles 101 to 102, and is shown in Tables 3 and 4.
○: The shape can be sufficiently maintained, and the rigidity is good. ×: The shape cannot be sufficiently maintained, and the rigidity is poor.

The modulus (EI) [N·mm ² ] was calculated from the load (W) [N] applied by the indenter, the deflection (δ) [mm] of the test piece, and the distance between supporting points (L) [mm] according to the following formula.
EI=[(ΔW/Δδ)×L ³ ]/(48)
Incidentally, ΔW/Δδ is calculated from the slope of a three-point bending test.

5. Overall Evaluation In the results of the transmission loss, mass, 10 mm width modulus, and stiffness evaluation, the case where there was an x rating was rated as x (bad) as an overall evaluation, and the case where there was no x rating was rated as o (good) as an overall evaluation. The results are shown in Tables 3 and 4.

As can be seen from Tables 3 and 4, the laminate of the example having a urethane foam layer with continuous and open cells, a flow resistance of 350,000 N·s/m4 or ^less , and a density of 10 kg/ ^m3 or more, and a resin layer containing a thermosetting resin, has a density of 50 kg/ ^m3 or more and 200 kg/ ^m3 or less, a modulus measured at a width of 10 mm of 0.01 N· ^m2 or more, a transmission loss greater than that of the molded product of the comparative example, excellent soundproofing properties, and excellent rigidity while maintaining a light weight.

The laminate of the present invention maintains rigidity, is lightweight, and has excellent soundproofing properties, particularly against high-frequency sounds, making it suitable for use as vehicle parts and building parts, and is particularly suitable for use as soundproof covers and engine covers.

Claims (7)

A urethane foam having continuous and open cells and a flow resistance of 350,000 N·s/m4 or less ^;
A resin composition containing glass fibers and a thermosetting resin.
A laminate having a urethane foam layer and a resin layer,
The density of the laminate is 50 kg/ ^m3 or more and 200 kg/ ^m3 or less, and the modulus measured at a width of 10 mm is 0.01 N ^m2 or more ,
The thickness of the urethane foam layer of the laminate is 27 mm or more,
The density of the urethane foam layer of the laminate is 10 kg/m3 or more ^,
The resin layer of the laminate has an areal density of 0.18 g/cm2 ^or more,
The modulus measured over a width of 10 mm was calculated by placing a test piece cut out from the laminate to a length of 100 mm and a width of 10 mm, with the resin layer facing up, on a three-point bending jig with a support distance set to 105 mm, and applying force with an indenter to the surface of the resin layer of the test piece to perform a three-point bending test . 2. The laminate according to claim 1, wherein the urethane foam layer of the laminate has a thickness of 50 mm or less. 3. The laminate according to claim 1 or 2 , which has a thickness of 55 mm or less . The laminate according to any one of claims 1 to 3, wherein the resin layer of the laminate has an areal density of 0.50 g/cm2 ^or less . The laminate according to any one of claims 1 to 4, wherein the thermosetting resin contains at least one of an unsaturated polyester resin, a vinyl ester resin, and a urethane resin. The laminate according to any one of claims 1 to 5, wherein the urethane foam layer of the laminate is adjacent to the resin layer of the laminate . A soundproofing material using the laminate described in any one of claims 1 to 6.