JP2001121638A - Laminated sheet and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated sheet excellent in lightweight properties, bending rigidity, compression regidity, heat moldability and dimensional stability and a method for producing the same. SOLUTION: In a laminated sheet wherein a reinforcing sheet is integrally laminated on one surface of a foamed sheet consisting of 100 part by weight of a thermoplastic resin and 1-100 part by weight of an inorganic filler, the aspect ratio Dz/Dxy of cells of the foamed sheet is 1.2 more and the expansion ratio thereof is 5-50 cc/g and the bending modulus gradient thereof 78.4 is N/50 mm/cm or more. Therefore, the laminated sheet is excellent in lightweight properties, bending rigidity, compression regidity, heat moldability and dimensional stability and suitably used as an interior material, a heat insulating material or a cushioning material for a car.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated sheet excellent in lightweight, bending rigidity, compressive rigidity, thermoformability and dimensional stability, and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, foams made of a thermoplastic resin have been used for various heat insulating materials, cushioning materials, flotation materials, etc. because of their excellent light weight, heat insulating properties and flexibility. Among them, polyolefin resin foams are particularly widely used for interior parts such as vehicle doors, ceilings, and instrument panels by secondary thermoforming due to their excellent heat resistance and dimensional stability. Have been.

JP-A-8-11254 proposes a composite foam suitable for an interior material for vehicles using a thermoplastic resin foam containing a polyolefin resin foam.

[0004] However, when the expansion ratio of the thermoplastic resin foam is increased in order to improve the lightness of the composite foam, the bending strength and the compression rigidity of the obtained composite foam are reduced, and the composite foam is used for vehicles. When used as a ceiling material, there is a problem that bending bending or breakage occurs at the time of processing or attachment to a vehicle, the attachment portion is dented, or the composite foam is damaged, and installation stability is impaired.

Further, in the related art, a peripheral member such as a lamp is attached to a vehicle interior material after the vehicle interior material is attached to the vehicle. Peripheral members such as lamps are attached to the material, and the mounting method of attaching the vehicle interior material with the peripheral member attached to the vehicle has been widely used, and the vehicle interior material has more bending rigidity and There is a demand for compression stiffness.

[0006]

SUMMARY OF THE INVENTION In view of the above problems, the present invention provides a laminated sheet which is excellent in light weight and excellent in bending rigidity, compressive rigidity, thermoformability and dimensional stability, and a method for producing the same. I do.

[0007]

Means for Solving the Problems The laminated sheet of the present invention comprises:
In a laminated sheet in which a reinforcing sheet is laminated and integrated on one surface of a foamed sheet composed of 100 parts by weight of a thermoplastic resin and 1 to 100 parts by weight of an inorganic filler, the foamed sheet includes:
The aspect ratio Dz / Dxy of the cell is 1.2 or more, the expansion ratio is 5 to 50 cc / g, and the bending elastic gradient is 78.4 N / 50 mm / cm or more.

[0008] The thermoplastic resin used for the foamed sheet is not particularly limited as long as it has been conventionally widely used for foams, and examples thereof include low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, and the like. Polyethylene such as high density polyethylene, isotactic polypropylene, polypropylene such as syndiotactic polypropylene, polybutene, polyolefin resins such as ethylene-α-olefin copolymer, ethylene-propylene-
Diene terpolymer, ethylene-vinyl acetate copolymer,
Ethylene-acrylic acid ester copolymer, polystyrene, polystyrene-based resin such as polystyrene-based thermoplastic resin elastomer and the like, and the resulting laminated sheet is excellent in light weight, chemical resistance, flexibility, and high elasticity. Polyolefin-based resins are preferred, polyethylene or polypropylene is more preferred, and a mixture of polyethylene and polypropylene is particularly preferred. In addition, the said thermoplastic resin may be used independently or may be used together.

The α-olefins include propylene, 1-butene, 1-pentene, 1-hexene,
Methyl-1-pentene, 1-heptene, 1-octene and the like are mentioned, and the copolymer containing an ethylene component is any of a block copolymer, a random copolymer and a random block copolymer. You may.

[0010] Further, if a polyolefin-based resin is added to a polyolefin-based resin, a laminated sheet excellent in light weight, chemical resistance, flexibility, high elasticity and mechanical strength can be obtained. In the above, if the content of the polystyrene resin is large, the excellent light weight, chemical resistance, flexibility, and high elasticity of the polyolefin resin are not exhibited, so that the total weight of the polyolefin resin and the polystyrene resin is 30% by weight. % Or less is preferable.

Further, since the thermoplastic resin needs to have a certain degree of elongational stress during foaming,
Conventionally, in order to impart a necessary elongation stress during foaming to a thermoplastic resin, a crosslinking structure has been imparted to the thermoplastic resin by, for example, irradiating ionizing radiation to the thermoplastic resin.

However, the above-mentioned crosslinking method can certainly impart a desired elongational stress to the thermoplastic resin, but the fluidity is often remarkably reduced, and the recycling is often difficult. was there.

In order to impart a fluidity and an elongation stress within a desired range at the time of foaming to the thermoplastic resin to obtain a foamed sheet excellent in light weight and recyclability, a radical reaction is performed as the thermoplastic resin. It is preferable to use a thermoplastic resin modified by grafting a modifying monomer having two or more functional groups that can be used.

That is, since the modified thermoplastic resin has elongation stress and fluidity suitable for foaming, when the laminated sheet is manufactured by using the method for manufacturing a laminated sheet described later, the foam of the foamed sheet is Can be easily and reliably adjusted so that the aspect ratio Dz / Dxy falls within a predetermined range, so that a laminated sheet having excellent compression rigidity can be reliably produced.

Moreover, since the modified thermoplastic resin has excellent fluidity, the laminated sheet obtained is excellent in moldability, and also has excellent elongation stress during foaming and low foaming pressure due to fluidity. The foamed sheet obtained is excellent in surface properties, and the resulting laminated sheet is also excellent in surface properties.Thus, the molded product obtained by molding the laminated sheet also has a complicated shape. And have excellent surface properties.

Examples of the modifying monomer include dioxime compounds, bismaleimide compounds, divinyl compounds, allyl polyfunctional compounds, (meth) acrylic polyfunctional compounds, and quinone compounds.

The dioxime compound includes the oxime group shown in Chemical formula 1 or a substituted oxime group shown in Chemical formula 2 in which a hydrogen atom in this oxime group is substituted with another atomic group R (mainly a hydrocarbon group). Means a compound having either one or two or both one by one,
Specific examples include p-quinone dioxime represented by Chemical formula 3, p, p'-dibenzoylquinone dioxime represented by Chemical formula 4, and the like. The dioxime compounds may be used alone or in combination.

[0018]

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[0019]

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[0020]

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[0021]

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The above-mentioned bismaleimide compound means a compound having two or more maleic imide (maleimide) structures shown in Chemical Formula 5 in the molecule. For example, N, N'-p-phenylene shown in Chemical Formula 6 Bismaleimide, N, N'-m-phenylenebismaleimide shown in Chemical formula 7, Chemical formula 8
And a polymaleimide having two or more maleimide structures in the molecule as shown in Chemical formula 9 is also included in the bismaleimide compound.

[0023]

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[0024]

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[0025]

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[0026]

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[0027]

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Examples of the divinyl compound include o-divinylbenzene, m-divinylbenzene and
p-divinylbenzene and the like.

[0029]

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The allyl-based polyfunctional compound means a compound having two or more allyl groups (CH ₂ ＣＨCHCH ₂ —) in the molecule. Examples include triallyl cyanurate as shown, triallyl isocyanurate as shown in Chemical formula 13, and diallyl chlorendate as shown in Chemical formula 14.

[0031]

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[0032]

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[0033]

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[0034]

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The above (meth) acrylic polyfunctional compounds include alkanediol di (meth) acrylate, ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, and polypropylene glycol di (meth) acrylate. (Meth) acrylate, neopentyl glycol di (meth) acrylate, dimethylol tricyclodecane di (meth) acrylate, ethylene glycol adduct di (meth) acrylate of bisphenol A, propylene glycol adduct di (meth) acrylate of bisphenol A Di (meth) acrylic compound such as trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, trimethylolpropane ethylene oxa De added tri (meth) acrylate,
Glycerin propylene oxide-added tri (meth) acrylate, tri (meth) acrylic compound such as tri (meth) acryloyloxyethyl phosphate, tetra (meth) acrylate such as pentaerythritol tetra (meth) acrylate, ditrimethylolpropanetetra (meth) acrylate Acrylate and the like.

Examples of the quinone compound include hydroquinone, p-benzoquinone, tetrachloro-p-benzoquinone and the like.

When the amount of the modifying monomer is large,
The crosslink density of the thermoplastic resin becomes too high and the recyclability decreases, or when the foamable thermoplastic resin sheet for obtaining the laminated sheet is extruded from the extruder, a high load is applied to the extruder or the melt fracture occurs. May occur, and if the amount is small, the necessary elongation stress may not be applied to the thermoplastic resin during foaming. Therefore, 0.05 to 5 parts by weight based on 100 parts by weight of the thermoplastic resin Parts by weight, more preferably 0.2 to 2 parts by weight.

In order to modify the thermoplastic resin by grafting the modifying monomer, the thermoplastic resin and the modifying monomer to which an organic peroxide is added, if necessary, are mixed with an extruder or a kneader. It can be carried out by supplying to a general-purpose melt-kneading apparatus and melting and kneading. When a divinyl compound or a diallyl compound is used as the modifying monomer, it is preferable to add an organic peroxide.

When the thermoplastic resin and the modifying monomer are melted and kneaded, if the resin temperature is high, the thermoplastic resin may be decomposed, and if the resin temperature is low, the modification of the thermoplastic resin becomes insufficient. Since the elongation stress during foaming of the expandable thermoplastic resin sheet becomes insufficient and a foam sheet having a desired expansion ratio may not be obtained, the temperature is preferably 170 ° C. or higher and the decomposition temperature of the thermoplastic resin or lower, 20
0-250 degreeC is more preferable.

Further, by improving the flowability of the thermoplastic resin modified by the modifying monomer as described above during foaming, the foaming pressure required for foaming can be further reduced, and the aspect ratio within a desired range described later can be improved. In order to more reliably obtain a foam having spindle-shaped cells having the following formula, it is preferable that an unmodified thermoplastic resin is further added to the modified thermoplastic resin, followed by melting and kneading. Note that the modified thermoplastic resin and the unmodified thermoplastic resin may be compatible with each other, and may be the same or different.

The organic peroxide is not particularly limited as long as it is generally used for grafting a thermoplastic resin, and examples thereof include benzoyl peroxide and benzoyl peroxide.
2,4-dichlorobenzoyl peroxide, t-butylperoxyacetate, t-butylperoxybenzoate, dicumyl peroxide, 2,5-dimethyl-
2,5-di (t-butylperoxy) hexane, di-t
-Butyl peroxide, 2,5-dimethyl-2,5-
Di (t-butylperoxy) -3-hexyne; and dicumyl peroxide, 2,5-dimethyl-2,
5-Di (t-butylperoxy) hexane and 2,5-dimethyl-2,5-di (t-butylperoxy) -3-hexyne are preferred. The above organic peroxides may be used alone or in combination.

When the amount of the above-mentioned organic peroxide is large, the so-called β is used when polypropylene is used as the thermoplastic resin.
The molecular weight of the modified thermoplastic resin obtained by remarkable cleavage may be too low to cause poor foaming due to a decrease in the physical properties and fluidity of the thermoplastic resin. Since the modification with the modifying monomer may become insufficient, the amount is preferably 0.001 to 0.5 part by weight based on 100 parts by weight of the thermoplastic resin.
The amount is more preferably from 0.5 to 0.15 parts by weight.

Examples of the inorganic filler include metal oxides such as titanium oxide, powdered inorganic fillers such as calcium carbonate, talc, kaolin clay, and mica; and balun-like inorganic fillers such as silas balun, glass balun, and fly ash balun. Among them, talc or mica is preferred among these, from the viewpoint that the effect of improving rigidity with respect to the thermoplastic resin is large and the dimensional stability of the obtained laminated sheet is excellent.

If the size of the inorganic filler is large, the foam may break during foaming of the expandable thermoplastic resin sheet, and a foam sheet having a high expansion ratio may not be obtained. Those having a particle size of 20 μm or less are preferred, and those having a particle size of 5 μm or less are more preferred.
Further, when the aspect ratio of the inorganic filler is large, the bending elastic gradient of the foamed sheet to be obtained is improved.

If the amount of the inorganic filler is large, the lightness of the obtained laminated sheet is reduced, and if it is small, the bending rigidity and the compression rigidity of the obtained laminated sheet are reduced.
The amount is limited to 1 to 100 parts by weight, preferably 5 to 30 parts by weight, per 100 parts by weight of the thermoplastic resin.

Most of the bubbles of the foamed sheet comprising the thermoplastic resin and the inorganic filler are formed in a spindle shape in which the length direction is directed to the thickness direction of the foamed sheet. In this way, the foamed sheet is formed to have excellent compression rigidity in the thickness direction by orienting most of the cells of the foamed sheet in a state in which the length direction thereof is oriented in the thickness direction of the foamed sheet. ing.

The foam sheet has an aspect ratio Dz /
When Dxy is small, the compression stiffness in the thickness direction of the obtained foamed sheet is reduced. Therefore, Dxy is limited to 1.2 or more.
The above is preferable, and 2 or more is particularly preferable.

The aspect ratio Dz / Dxy of the cells of the foam sheet is measured in the following manner. That is, first, the foamed sheet is cut in the thickness direction, and the length Dz of the foamed sheet in the thickness direction of the foamed sheet and the thickness direction of the foamed sheet are perpendicular to the cut surface and are along the cut surface. By measuring the length Dxy in the direction, the aspect ratio (Dz / Dxy) of each bubble is calculated. Then, the average value of the obtained aspect ratios (Dz / Dxy) of the respective cells is calculated, and is set as the aspect ratio Dz / Dxy of the cells of the foam sheet.

When the foaming ratio of the foamed sheet is high, the mechanical strength such as the compression rigidity and bending rigidity of the obtained laminated sheet decreases, and when the foaming ratio is low, the lightweight property of the obtained laminated sheet decreases. Limited to 5-50 cc / g, 10-3
0 cc / g is preferred. The expansion ratio of the foam sheet is measured according to JIS K6767, and is the reciprocal of the apparent density.

When the bending elastic gradient of the foamed sheet is low, the bending strength of the foamed sheet is reduced.
/ 50mm / cm or more, 117.6N / 50
mm / cm is preferable, and 156.8 N / 50 mm / cm
Is more preferred.

The bending elastic gradient of the foam sheet is as follows.
This is a value indicating resistance to a load applied in the thickness direction of the foamed sheet, and is a value obtained by measuring a foamed sheet having a length of 15 cm, a width of 50 mm and a thickness of 6 mm in accordance with JIS K7203.

The laminated sheet of the present invention is formed by laminating and integrating a reinforcing sheet on one side of the above foam sheet, preferably on both sides. Examples of the reinforcing sheet include a dry thermal bonding method, a needle punching method and a wet type. Thermal nonwoven fabrics made from inorganic fibers such as glass fibers and carbon fibers by a papermaking method carried out in, thermal face mat, cloth woven roving, glass cloth and the like produced by weaving glass fibers or carbon fibers, and the like. A thermal face mat which is a nonwoven fabric made of glass fiber or carbon fiber by a wet papermaking method is preferable. In addition, when the reinforcing sheet is laminated and integrated on both sides of the foam sheet, the reinforcing sheets to be laminated and integrated on both sides of the foam sheet may be of different types,
From the viewpoint of the dimensional stability of the obtained laminated sheet, it is preferable to use the same type of reinforcing sheet laminated and integrated on both sides of the foamed sheet.

When the inorganic fibers constituting the thermal face mat are glass fibers, the diameter of the glass fibers is 8
To 25 μm, and the length of the glass fiber is preferably 30 mm or less. When the inorganic fibers constituting the thermal face mat are carbon fibers, the diameter of the carbon fibers is 4
To 15 μm, and the carbon fiber preferably has a length of 30 mm or less. Further, the thermal face mat preferably has a thickness of 10 μm to 1 mm and a weight of 10 to 50 g / m ² .

The thermal face mat contains a binder for binding the inorganic fibers to each other. Examples of such a binder include polyvinyl alcohol-based resins, saturated polyester-based resins, unsaturated polyester-based resins, and the like. Acrylic resins such as polymethyl (meth) acrylate, polybutyl (meth) acrylate, poly-n-tetradecyl (meth) acrylate, poly-n-propyl (meth) acrylate, polyisobutyl (meth) acrylate, and linear urethane resins Urethane resin,
Examples include epoxy resins, phthalic acid derivatives such as dimethyl phthalate and dimethyl isophthalate, and thermoplastic resins such as vinyl acetate resins.

The glass transition temperature Tg of the binder is as follows:
If it is too high, the moldability of the obtained laminated sheet may be reduced, and if it is low, the strength of the obtained thermal face mat may be reduced.

The tensile strength of the reinforcing sheet is preferably at least 2.94 N / cm ² for the following reason. That is, as described below, the laminated sheet is manufactured by foaming a foamable laminated sheet obtained by laminating and integrating a reinforcing sheet on one surface of a foamable thermoplastic resin sheet. The foaming of the foamable thermoplastic resin sheet in the surface direction is regulated by the reinforcing sheet, while the foaming of the foamable thermoplastic resin sheet in the thickness direction is in a free foaming state. Oriented in the thickness direction of the plastic resin sheet, the cells of the obtained foamed sheet are formed into a spindle shape whose length direction is oriented in the thickness direction of the foamed sheet, that is, the aspect ratio Dz / Dxy is within a predetermined range described later. It is formed to be inside.

Therefore, when the tensile strength of the reinforcing sheet is low, the foaming of the foamable thermoplastic resin sheet in the surface direction cannot be effectively restricted by the reinforcing sheet, and the bubbles of the foamed sheet obtained cannot be effectively controlled. This is because the aspect ratio Dz / Dxy does not fall within the predetermined range, and it may not be possible to impart a desired compression rigidity to the obtained laminated sheet.

Further, when the linear expansion coefficient of the reinforcing sheet is large, the linear expansion coefficient of the obtained laminated sheet is also increased, and the degree of expansion and contraction of the laminated sheet due to temperature change is increased, and the dimensional stability is reduced. since it may be or have drooping by its own weight in, preferably 5 × 10 ^-5 / ℃ or less, more preferably 1 × 10 ^-5 / ℃ or less.

Further, a surface layer may be laminated and integrated on the surface of the reinforcing sheet. By thus further laminating and integrating the surface layer on the surface of the reinforcing sheet, the reinforcing sheet is formed from inorganic fibers. In such a case, it plays a role of a binder for binding the inorganic fibers to each other, and can reduce the coefficient of linear expansion of the reinforcing sheet, and thus can make the obtained laminated sheet excellent in dimensional stability. . When the reinforcing sheet is laminated and integrated on both sides of the foam sheet, the surface layer may be laminated and integrated only on the surface of one of the reinforcing sheets.

Examples of the surface layer include films made of thermoplastic resins such as polystyrene, polyethylene, polypropylene, polybutene, nylon, and polyethylene terephthalate.

When a film made of a thermoplastic resin is used as the surface layer and a sheet made of inorganic fibers is used as the reinforcing sheet, the thermoplastic resin constituting the surface layer is made of the reinforcing sheet. Since it also serves as an adhesive between the reinforcing sheet and the foamed sheet by entering between the inorganic fibers constituting the foamed sheet, the thermoplastic resin constituting the surface layer is a thermoplastic resin constituting the foamed sheet. Preferably, they have compatibility.

When the thickness of the surface layer is large, the lightness of the obtained laminated sheet may be reduced. When the thickness is small, the effect of laminating and integrating the surface layer on the reinforcing sheet is not exhibited. Therefore, 10 to 200 μm is preferable.

Next, a method of manufacturing the laminated sheet will be described. As a method for producing the laminated sheet, for example, a reinforcing sheet is laminated and integrated on one or both surfaces of a foamable thermoplastic resin sheet composed of a thermoplastic resin and a foaming agent, and further, if necessary, a surface is formed on the reinforcing sheet. A method for producing the laminated sheet by laminating and integrating the thermoplastic resin film constituting the layer to form a foamable laminated sheet, and foaming the foamable laminated sheet,
A reinforcing sheet is superimposed on one or both surfaces of a foamable thermoplastic resin sheet composed of a thermoplastic resin and a foaming agent, and further, if necessary, by laminating the thermoplastic resin film constituting a surface layer on the reinforcing sheet. Forming a foamable laminated sheet, foaming the foamable laminated sheet at the same time as foaming the foamable thermoplastic resin sheet and a reinforcing sheet, and, if necessary, integrating the thermoplastic resin film as well. And a method for producing the above laminated sheet.

The foaming agent is not particularly limited as long as it is widely used in the production of foams. Inorganic thermal decomposition such as sodium bicarbonate, ammonium carbonate, ammonium bicarbonate, and azide compound is used. Foaming agent, azodicarbonamide, azobisisobutyronitrile, dinitrosopentamethylenetetramine, benzenesulfonylhydrazide, toluenesulfonylhydrazide, 4,4
-Oxybis (benzenesulfonylhydrazide), barium azodicarboxylate, trihydrazinotriazine, p
Organic pyrolysis-type foaming agents such as toluenesulfonyl semicarbazide.

If the amount of the foaming agent is large, the foam may be broken. If the amount is small, the foam may not be foamed. Therefore, 1 to 50 parts by weight per 100 parts by weight of the thermoplastic resin is used. preferable.

As a method for producing the foamable thermoplastic resin sheet, for example, a thermoplastic resin is supplied to an extruder, melted and kneaded, and a foaming agent is added to the molten thermoplastic resin. A method of producing a foamable thermoplastic resin sheet by uniformly dispersing a foaming agent in a resin and extruding the foamed sheet into a sheet shape is exemplified.

When using a modified thermoplastic resin which is modified by adding a modifying monomer as a thermoplastic resin and grafting the modified thermoplastic resin, the thermoplastic resin and the modifying monomer are supplied to an extruder, melted and kneaded. After the thermoplastic resin is grafted and modified, the foaming agent is uniformly dispersed in the modified thermoplastic resin by adding a foaming agent to the modified thermoplastic resin in a molten state, and then extruded into a sheet to form a foam. A method for producing a thermoplastic resin sheet is exemplified.

Examples of a method of laminating and integrating a reinforcing sheet on one surface of the expandable thermoplastic resin sheet include, for example, a method of laminating and integrating a reinforcing sheet on one surface of an expandable thermoplastic resin sheet while heating the sheet. A method in which a reinforcing sheet is pressed onto one surface of a foamed thermoplastic resin sheet in a molten state and laminated and integrated, that is, a foamable thermoplastic resin sheet is extruded from a T-die attached to the tip of an extruder, and After placing the reinforcing sheet on one side of the foamable thermoplastic resin sheet whose surface immediately after extrusion is in a molten state,
A method in which a reinforcing sheet is laminated and integrated on one surface of an expandable thermoplastic resin sheet by supplying the sheet between a pair of cooling rolls, sandwiching and integrating the expandable thermoplastic resin sheet with the cooling rolls, and an expandable thermoplastic resin. A method in which the sheet and the reinforcing sheet are laminated and integrated via an adhesive is exemplified, and the above method is preferable because the thickness of the foamable laminated sheet can be finely adjusted.

When a surface layer is further laminated and integrated on the surface of the reinforcing sheet, for example, a reinforcing sheet and a thermoplastic resin film are provided on one side of the expandable thermoplastic resin sheet, and the reinforcing sheet is on the inner side. And then heating the thermoplastic resin film above the softening temperature or higher, and laminating and integrating a surface layer comprising a reinforcing sheet and a thermoplastic resin film on one surface of the foamable thermoplastic resin sheet. .

As a method for heating the foamed laminated sheet manufactured as described above, a general-purpose heating apparatus conventionally used for manufacturing a foamed body is used. For example, a pair of heating apparatuses arranged in a facing state is used. A roll-type heating device or a belt-type heating device for supplying a foamable laminated sheet between heating rolls or heating belts to heat the foamable laminated sheet, a hot-air constant temperature bath for blowing hot air to the foamable laminated sheet, a foamable laminated sheet Bath, metal bath, salt bath and the like.

When the expandable thermoplastic resin sheet of the expandable laminated sheet is expanded in the above manner, the expansion of the expandable thermoplastic resin sheet is performed by laminating and integrating the reinforcing sheet on one surface of the expandable thermoplastic resin sheet. Therefore, while the foaming in the plane direction is regulated by the reinforcing sheet,
The foaming in the thickness direction is in a free foaming state without being restricted by the reinforcing sheet.

However, the foaming direction of the foamable thermoplastic resin sheet is regulated in a state of being oriented in the thickness direction, and the bubbles of the foamable sheet obtained by foaming the foamable thermoplastic resin sheet are as follows: The length direction is directed to the thickness direction of the foamable sheet, and the aspect ratio D within a predetermined range.
It is formed in a spindle shape having z / Dxy.

Therefore, most of the cells of the foamed sheet are formed into a spindle shape with the length direction oriented in the thickness direction of the foamed sheet. It is formed to have excellent compressive rigidity in the thickness direction while maintaining the property. Moreover, since the laminated sheet is formed by laminating and integrating a reinforcing sheet on one surface of the foamed sheet, it is excellent in bending rigidity.

Furthermore, since the above-mentioned laminated sheet is formed by laminating and integrating a reinforcing sheet on one side of a foamed sheet having excellent formability, a hot press method of performing heat molding with a general compression molding machine, and a method of forming a foamed sheet. After being heated to a temperature higher than the softening point, the foamed sheet can be formed into a desired shape by a general-purpose molding method such as a cold press method or a vacuum molding method in which shape transfer is performed in a mold maintained at a temperature lower than the softening point.

[0075]

The laminated sheet of the present invention has a foamed sheet containing a predetermined amount of an inorganic filler as a constituent element, and a reinforcing sheet is laminated and integrated on one surface of the foamed sheet. The sheet has bubbles with the length direction directed in the thickness direction of the laminated sheet and has an aspect ratio Dz / Dxy of 1.2 or more and 78.4 N /
Since it has a bending elastic gradient of 50 mm / cm or more, it has excellent bending rigidity and compressive rigidity in the thickness direction.

In particular, in the foamed sheet of the laminated sheet, the bubbles are directed in the length direction to the thickness direction of the laminated sheet and have an aspect ratio Dz / Dxy within a predetermined range. Even if it does, it maintains excellent compression stiffness in the thickness direction.

Therefore, in the laminated sheet of the present invention, the amount of the inorganic filler in the foamed sheet can be reduced as much as possible, and a foamed sheet having a high expansion ratio can be used. It is formed to have excellent bending rigidity and compression rigidity while holding.

The laminated sheet of the present invention has excellent dimensional stability with almost no dimensional change due to temperature change because the reinforcing sheet is laminated and integrated on one surface of the foamed sheet.

Further, when a surface layer is laminated and integrated on the surface of the reinforcing sheet of the laminated sheet, the surface layer plays a role of reinforcing the reinforcing sheet. The obtained laminated sheet has more excellent mechanical rigidity such as bending rigidity and compressive rigidity.

In addition, when the reinforcing sheet of the laminated sheet is made of glass fiber or carbon fiber sheet as described in claim 3, the reinforcing sheet has excellent moldability, and The resulting laminated sheet has excellent moldability. In addition, when the surface layer is laminated and integrated on the surface of the reinforcing sheet, the surface layer enters between the glass fibers or carbon fibers constituting the reinforcing sheet and serves as a binder to improve the rigidity of the reinforcing sheet. Therefore, the obtained laminated sheet is further excellent in mechanical rigidity such as bending rigidity and compressive rigidity.

In producing the laminated sheet, a reinforcing sheet is laminated on one side of the expandable thermoplastic resin sheet to form an expandable laminated sheet, and then the expandable laminated sheet is heated. If the method for producing a laminated sheet to be foamed is used, a foamable laminated sheet is manufactured by a simple operation of laminating a reinforcing sheet on one side of a foamable thermoplastic resin sheet, and then foaming is performed using a general-purpose heating means. By foaming the laminated sheet, it is possible to easily and surely produce a laminated sheet having excellent mechanical rigidity such as bending rigidity and compressive rigidity as described above and excellent in lightness, dimensional stability and formability. it can.

[0082]

EXAMPLES (Example 1) The following equipment was used to produce a foamable polypropylene sheet. That is, a co-rotating twin screw extruder (Plastic Engineering Laboratory Co., Ltd.)
A co-rotating twin screw extruder (trade name "TEX-4" manufactured by Nippon Steel Works Co., Ltd.) via an adapter at the tip of a trade name "BT40" (hereinafter referred to as "first extruder").
4 ", hereinafter referred to as" second extruder ").

The first extruder was equipped with a self-wiping double screw, and its L / D was 35 and D (diameter) was 39 m.
m. The cylinder barrel is divided from the first barrel to the fourth barrel from the upstream to the downstream of the extruder, and the tip of the fourth barrel can be continuously connected to a TEX-44 type co-rotating twin screw extruder described later. An adapter is provided.

A vacuum vent is provided in the fourth barrel in order to recover components volatilized in the cylinder barrel, in particular, a modifying monomer. In the following operation, the temperature of the first barrel was set to 180 ° C., the temperature of the second barrel to the fourth barrel was set to 220 ° C., and the screw rotation speed was set to 150 rpm.

The second extruder was equipped with a self-wiping double screw, and its L / D was 45.5 and D was 47 m.
m. The cylinder barrel is divided into a first barrel to a twelfth barrel from upstream to downstream of the extruder,
A coat hanger die having a width of 500 mm is attached to the tip of the two barrels.

Further, a side feeder is provided in the sixth barrel to supply the foaming agent, and a vacuum vent is provided in the eleventh barrel to collect the components volatilized in the cylinder barrel.

In the following operation, the first barrel is constantly cooled, and the temperature of the second barrel to the fourth barrel is reduced to 150 ° C.
The temperature of the fifth barrel to the eighth barrel was set to 170 ° C., the temperature of the ninth barrel to the twelfth barrel was set to 180 ° C., the temperature of the adapter and the coat hanger die was set to 160 ° C., and the screw rotation speed was set to 40 rpm. .

A random type of polypropylene (manufactured by Nippon Polychem Co., Ltd., melt index = 0.8) was placed in a hopper integrally provided at the rear end of the first barrel of the first extruder.
g / 10 min, density = 0.9 g / cm ³ ) and p-quinone dioxime (trade name “Varnock GM-P” manufactured by Ouchi Shinko Chemical Co., Ltd.) as a modifying monomer, and melted.
The modified polypropylene was produced by kneading, and the obtained modified polypropylene was continuously supplied to a second extruder via an adapter. The amount of the above polypropylene was 10 kg / h, and the amount of the p-quinone dioxime was 0.08 kg / h.

Further, pellet-like talc (manufactured by Tokuyama Co., Ltd.) is supplied from a hopper provided at the rear end of the first barrel of the second extruder.
Product name “T68MMR”, particle size = 5 μm, talc content = 70% by weight) and unmodified homopolypropylene (product name “MA3” manufactured by Nippon Polychem Co., Ltd., melt index =
10 g / min, density = 0.91 g / cm ³ ), azodicarbonamide was supplied from a side feeder provided in the sixth barrel of the second extruder, and was continuously fed from the first extruder. Supplied modified polypropylene,
Talc, unmodified homopolypropylene and azodicarbonamide were melted and kneaded, and a foamable polypropylene sheet having a thickness of 0.4 mm was obtained from a coat hanger die attached to the tip of the second extruder. The expandable polypropylene sheet contained 25 parts by weight of talc based on 100 parts by weight of the modified polypropylene. The input amount of talc was 5.7 kg / h, the input amount of unmodified homopolypropylene was 4.3 kg / h, and the input amount of azodicarbonamide was 2 kg / h.

On the other hand, a continuous sheet-shaped paper having a width of 500 mm
Spaper (Olivest product name "SUO-025"
C ", coefficient of linear expansion = 0.4 × 10^-Five/ ° C, weight = 25 g
/ M ^Two, Thickness = 0.22 mm, glass fiber diameter = 9 μm,
Glass fiber length = 25 mm, binder = polyvinyl alcohol
70% by weight coal and 30% by weight thermoplastic urethane resin
%) On one side, a width of 500 mm and a thickness of 80 μm
Homo-based polypropylene (Tokuyama's product name "SH-
152 ", melt index = 15 g / min, density =
0.91 g / cm^ThreeBy heat laminating)
The laminate was integrated to obtain a laminated face material.

Then, the foamed laminated sheet obtained by laminating the laminated face material on both sides of the foamable polypropylene sheet so that the glass paper is on the inside is supplied to a belt type heating device and heated to 230 ° C. Then, while foaming the expandable polypropylene sheet, and by foaming the expandable polypropylene sheet, by pressing the laminated face material on each side of the foam sheet obtained by foaming the foamed polypropylene sheet, the two are integrated, and then cooled to a thickness. A 6 mm-thick laminated sheet was obtained.

As shown in FIG. 1, the belt-type heating device is provided with a preheating zone 1, a foaming zone 2, a cooling zone 3, and a fixed vertical direction extending over these three zones. It consists of a pair of conveyor belts 4 arranged at intervals, and the foamable laminated sheet is placed on the upper surface of the lower conveyor belt of the pair of conveyor belts 4, and the foamable laminated sheet is placed in the preheating zone 1, The foamed laminated sheet is fed in the order of the foaming zone 2 and the cooling zone 3 to foam the foamed laminated sheet between the opposing inner surfaces, and the foaming laminated sheet 5 being foamed is sandwiched between the opposing inner surfaces of the pair of conveyor belts 4 from above and below. , Pressed.

Example 2 An extruder was used in which a 3-hole strand die was attached instead of the adapter used to connect the second extruder to the tip of the first extruder used in Example 1. A random type polypropylene (manufactured by Nippon Polychem Co., Ltd., melt index = 0.8 g / 10 minutes,
Density = 0.9 g / cm ³ ) and p-
Quinone dioxime (Ouchi Shinko Chemical Co., Ltd. product name "Barnock GM-P") is supplied, melted and kneaded,
After extruding the modified polypropylene from a three-hole strand die, it was cooled with water, and cut into a predetermined length with a pelletizer to obtain a pellet-shaped modified polypropylene.

Next, 20 parts by weight of the above-mentioned pellet-shaped modified polypropylene, 10 parts by weight of calcium carbonate (trade name “ML180-3” manufactured by Calp Industries, particle size = 5 μm, calcium carbonate content = 80% by weight), and Modified homopolypropylene (trade name "MA" manufactured by Japan Nippon Polychem Co., Ltd.
7 ", melt index = 1.2 g / min, density = 0.
91 g / cm ³ ), 10 parts by weight, was supplied to Labo Plastomill (trade name “100C100”, manufactured by Toyo Seiki Seisaku-sho, Ltd.) and melted and kneaded at 170 ° C. and 60 rpm for 5 minutes. To this, 2.4 parts by weight of azodicarbonamide was further added, melted and kneaded to obtain an expandable polypropylene. This expandable polypropylene contained 25 parts by weight of calcium carbonate with respect to 100 parts by weight of the total of the modified polypropylene and the unmodified polypropylene. Then, the obtained expandable polypropylene was molded at a molding temperature of 18 using a press molding machine.
Formed into a sheet under the conditions of 0 ° C., a molding pressure of 1470 N / cm ² , and a molding time of 3 minutes, 150 mm long × 150 mm wide
X A foamable polypropylene sheet having a thickness of 0.4 mm was obtained.

Next, the laminated face material prepared in Example 1 was superimposed on both sides of the obtained foamable polypropylene sheet so that the glass paper was on the inside, and then supplied to a press molding machine. The two were integrated to obtain a foamed laminated sheet.

The lamination and integration of the expandable polypropylene sheet and the laminated face material in the press molding machine were performed under the conditions of a temperature of 180 ° C., a pressure of 1470 N / cm ² and a molding time of 3 minutes.

Then, the foamable laminated sheet was supplied into a hot-air constant temperature bath and heated at 220 ° C. for 8 minutes, whereby
The foamable polypropylene sheet was foamed to obtain a laminated sheet having a thickness of 6 mm.

(Example 3) 20 parts by weight of modified polypropylene in pellet form, 17 parts by weight of talc in pellet form (trade name “T68MMR” manufactured by Tokuyama Corporation, particle size = 5 μm, talc content = 70% by weight), Modified homopolypropylene (trade name “MA7”, manufactured by Japan Nippon Polychem Co., Ltd., melt index = 1.2 g / min, density = 0.91 g / c)
m ³ ) Example 2 was repeated except that 3 parts by weight was supplied to Labo Plastomill (trade name “100C100” manufactured by Toyo Seiki Seisaku-sho, Ltd.) and the amount of azodicarbonamide added was 3.1 parts by weight. Similarly, a laminated sheet having a thickness of 6 mm was obtained.

The foamable polypropylene sheet includes:
Total amount of modified polypropylene and unmodified polypropylene 1
43 parts by weight of calcium carbonate was contained with respect to 00 parts by weight, and the thickness was 0.31 mm.

(Comparative Example 1) A pellet-like talc was not added, and unmodified homopolypropylene (trade name “MA3” manufactured by Nippon Polychem Co., Ltd., melt index = 1)
0 g / min, density = 0.91 g / cm ³ )
A laminated sheet was obtained in the same manner as in Example 1 except that the weight was set to kg / h.

Comparative Example 2 16 parts by weight of modified polypropylene in pellet form, 24 parts by weight of talc (particle size = 5 μm) and unmodified homopolypropylene (trade name “MA7” manufactured by Nippon Polychem Co., Ltd., melt index = 1. 2g /
Min, density = 0.91 g / cm ³ ) 10 parts by weight were supplied to Labo Plastmill, and azodicarbonamide was
Except for adding 8 parts by weight, a foamable polypropylene sheet having a thickness of 0.25 mm was obtained in the same manner as in Example 2. This expandable polypropylene contained 150 parts by weight of talc based on 100 parts by weight of the total of the modified polypropylene and the unmodified polypropylene.

Then, a foamed laminated sheet was prepared using the foamable polypropylene sheet in the same manner as in Example 2, and the foamed laminated sheet was foamed to a thickness of 1.2.
mm laminated sheet was obtained.

Comparative Example 3 Aspect Ratio Dz / Dxy of Bubbles
Is a crosslinked polypropylene sheet (Sekisui Chemical Co., Ltd.)
Product name "Softlon SP", expansion ratio = 15 cc / g,
The laminated face material prepared in Example 1 was laminated and integrated on each of both surfaces (thickness = 5.5 mm) to obtain a weight of 600 g / cm ² ,
A laminated sheet having a thickness of 6.0 mm was obtained.

The expansion ratio of the foamed sheets of the laminated sheets obtained in Examples 1 to 3 and Comparative Examples 1 to 3,
The bending elastic gradient, the aspect ratio Dz / Dxy, and the linear expansion coefficient of the reinforcing sheet were measured by the following method.
It was shown to.

(Expansion ratio) Measured in accordance with JIS K6767.

(Bending elastic gradient) A predetermined expansion ratio (15 c
c / g), a test piece having a length of 15 cm, a width of 50 mm and a thickness of 6.0 mm was cut out from the foamed sheet, and the bending elastic gradient of the test piece was measured according to JIS K72.
03.

(Coefficient of linear expansion) Length 150 from foam sheet
A test piece having a size of 20 mm × width 20 mm × thickness 6.0 mm is cut out, left in an atmosphere at 85 ° C. for 24 hours, and marked with a mark having a space of 130 mm on the surface of the test piece. Then, immediately after the test piece is left in a constant temperature bath at 80 ° C. for 6 hours, the length between the front lines (L ₈₀ ) is measured. Next, the test piece was left in a thermostat at 0 ° C. for 6 hours, and then the length between the marked lines (L ₀ ) was measured.
The linear expansion coefficient is calculated by the following equation.

Α = (L ₀ −L ₈₀ ) / (L ₀ × 80)

[0109]

[Table 1]

[0110]

Since the laminated sheet of the present invention has the above-mentioned structure, it is excellent in lightness and flexural rigidity.
It has excellent compression rigidity, heat shapeability and dimensional stability, and is suitably used for interior materials for automobiles, heat insulating materials, cushioning materials and the like.

According to the method for producing a laminated sheet of the present invention, a reinforcing sheet is laminated on one surface of a foamable thermoplastic resin sheet to obtain a foamable laminated sheet, and then the foamable laminated sheet is subjected to general-purpose heating. The above-mentioned laminated sheet can be reliably obtained by a simple process such as foaming using an apparatus.

[Brief description of the drawings]

FIG. 1 is a schematic side view showing a heating device used in an example.

[Explanation of symbols]

 Reference Signs List 1 preheating zone 2 foaming zone 3 cooling zone 4 transport belt

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4F100 AA01A AD11B AG00B AK01A AK07 AK51 BA02 CA23A DG01B DG03 DH00B DJ01A DJ04A EH012 EJ022 EJ17 EJ422 GB33 JA13A JA20A JB16A JK04 JK05 JK07 AJA12A03A03 UB02 UB13 UB22 UE27 UG05

Claims (4)

[Claims] 1. A laminated sheet in which a reinforcing sheet is laminated and integrated on one surface of a foamed sheet comprising 100 parts by weight of a thermoplastic resin and 1 to 100 parts by weight of an inorganic filler, wherein the foamed sheet has an aspect ratio of air bubbles. Dz / Dxy is 1.
2 or more, and its expansion ratio is 5 to 50 cc / g, and its bending elastic gradient is 78.4 N / 50 mm / cm.
A laminated sheet characterized by the above. 2. The laminated sheet according to claim 1, wherein a surface layer is laminated and integrated on the surface of the reinforcing sheet. 3. The laminated sheet according to claim 1, wherein the reinforcing sheet is formed from a glass fiber sheet or a carbon fiber sheet. 4. A foamed laminated sheet is formed by laminating a reinforcing sheet on one side of a foamable thermoplastic resin sheet comprising 100 parts by weight of a thermoplastic resin, 1 to 100 parts by weight of an inorganic filler and 1 to 50 parts by weight of a foaming agent. After forming, the foamable laminated sheet is heated and foamed.
The method for producing a laminated sheet according to any one of the above.