JPH0872628A - Base material for forming interior material for automobile - Google Patents

Abstract

PURPOSE: To provide a base material for forming an interior material for an automobile, which will not cause a trouble at the time of construction as the mechanical strength is large, and is excellent in respect of thermal dimensional stability and form retention. CONSTITUTION: A polycarbonate resin extruded foamed sheet with the density of 0.06-0.24g/cm<3> , the average value of maximum diameter of bubbles of 0.1-0.7mm, and a thickness of 2-8mm is used as a core material, a polycarbonate resin film is stacked on both surfaces of the foamed sheet, or a fibrous woven fabric or non-woven fabric is stacked on at least one surface thereof, the viscosity average molecular weight of polycarbonate resin for the foamed sheet is 2,0000 or more, and the viscosity average molecular weight of polycarbonate resin for the film is less than 2,0000. Further, the resin is formed in such a manner that the forms of bubbles satisfy fixed conditions.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automobile interior material molding base material having high dimensional stability at high temperatures.

[0002]

2. Description of the Related Art Foamed resin sheets have been widely used as thermoforming materials for manufacturing automobile interior ceiling materials and the like. In addition, the temperature inside the automobile in summer becomes abnormally high (especially near the ceiling), so that the base material for automobile interior materials is resistant to that temperature, and hangs down even after long-term use in hot or cold atmospheres. A material that does not deform is required.
In order to meet such requirements, the resin foam sheet for the interior material has been used that has high heat resistance and good shape retention after molding. That is, a foamed sheet using a styrene-based copolymer such as a styrene-maleic anhydride copolymer or a styrene-methacrylic acid copolymer (Japanese Patent Publication No. 63-45936) as a base resin has been used.

The interior material formed of the styrene copolymer or the like is superior to the interior material formed of the polystyrene resin foam sheet, but the heat resistance and shape retention are not satisfactory. The heat resistance of the styrene-based copolymer can be improved by further increasing the amount of the copolymerization component, but if the amount of the copolymerization component is too large, it becomes difficult to produce a good copolymer, and therefore the styrene-based copolymer is The heat resistance is limited in the foamed sheet using the united body as a base material. To improve this, Japanese Patent Laid-Open No.
Japanese Patent No. 124054 proposes a foamed sheet based on a modified polystyrene-based resin with polyphenylene ether. However, when the polyphenylene ether content is high, the heat resistance increases, but it becomes difficult to form a good foam sheet, and therefore, a foam sheet having satisfactory heat resistance and shape retention has not been obtained. Also, as mentioned above, most of the foamed sheets used for interior materials are made of polystyrene resin, but this type of resin causes "break" and "breakage" when punching holes by punching. Therefore, the yield is deteriorated when punching is required when manufacturing an automobile interior material.

There has been an attempt to use a polycarbonate resin having a high heat resistance as an interior material for automobiles. Then, there has been proposed a method of foaming a polycarbonate resin having a molecular weight of 30,000 to 40,000 by impregnation foaming using carbon dioxide as a foaming agent (JP-A-6-80813). However, since the foamed polycarbonate resin sheet manufactured by these conventional methods has fine bubbles, it does not shrink at the time of molding heating and expands conversely, so that a phenomenon called drawdown occurs at the time of molding. This is a phenomenon that the foam sheet hangs down,
When this occurs, heating is often uneven, resulting in defective molding. As described above, since an ideal base material for molding automobile interior materials has not been obtained, we have developed a base material for forming automobile interior materials that has excellent heat resistance and rigidity, as well as high impact resistance and shape retention. Is required.

[0005]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems in materials used as interior materials in automobiles, and has high mechanical strength such as rigidity and impact resistance. It is an object of the present invention to provide a base material for molding an automobile interior material, which is excellent in properties, thermal dimensional stability and shape retention.

[0006]

The present inventors have completed the present invention as a result of intensive studies to achieve the above object. That is, according to the present invention, the density is 0.06 to
0.24 g / cm ³ , average value of maximum diameter of bubbles 0.1 to
Provided is a base material for molding an automobile interior material, which comprises a polycarbonate resin extruded foam sheet having a thickness of 0.7 mm and a thickness of 2 to 8 mm as a core material, and a polycarbonate resin film laminated on both surfaces of the foam sheet. Also,
According to the invention, a density of 0.06 to 0.24 g / cm ³ ,
Average maximum bubble diameter 0.1-0.7 mm, thickness 2-8
Provided is a base material for molding an automobile interior material, which comprises a polycarbonate resin extruded foam sheet of mm as a core material, and a woven or non-woven fabric made of fibers is laminated on at least one surface of the foam sheet. It

Further, according to the present invention, the base resin of the foamed sheet is a polycarbonate resin having a viscosity average molecular weight of 20,000 or more, and the base resin of the film is a polycarbonate resin having a viscosity average molecular weight of less than 20,000. The above-mentioned base material for molding an automobile interior material is provided. Furthermore, according to the present invention, there is provided the above-mentioned automobile interior material molding base material, in which bubbles are formed so as to satisfy the following conditional expressions. 1 <X / Z ≦ 3 1 <Y / Z ≦ 5 [where X is the average cell diameter (mm) in the direction orthogonal to the thickness direction of the sheet width direction cross section, and Y is orthogonal to the thickness direction of the sheet extrusion direction cross section] The average bubble diameter (mm) in the direction
Z represents the average cell diameter (mm) in the thickness direction of the sheet cross section]

The automobile interior material molding base material of the present invention uses a polycarbonate resin, which has not been used as a base material, until now. Further, since the polycarbonate resin has significantly higher heat resistance than general-purpose thermoplastic resins such as polystyrene, it is a base material in which the heat resistance problem found in the conventional base material is drastically improved. The automobile interior material molding base material of the present invention is a laminate having appropriate thickness and strength so that the interior of the automobile is not narrowed and the rigidity, sound absorption and cushioning properties are not deteriorated. That is, a polycarbonate resin extruded foam sheet having a thickness of 2 to 8 mm, preferably 3 to 5 mm is used as a core material, and both surfaces thereof have a thickness of 0.1 to 0.3 mm, preferably 0.15 to 0.25 m.
m polycarbonate resin film is laminated, or a thickness of 0.1-1.
It is a laminated body in which a woven or non-woven fabric made of fiber having a thickness of 5 mm, preferably 0.2 to 0.5 mm is laminated. When the foamed sheet is used as a base material as it is, the interior material is poor in shape retention due to insufficient mechanical strength and sufficient bending rigidity cannot be obtained. Further, the improvement of the mechanical strength can be achieved only by laminating on one surface of the foamed sheet, but laminating the polycarbonate resin film on only one surface facilitates curling of the foamed sheet.

The density of the foamed sheet is 0.06 to 0.2.
4 g / cm ³ , preferably 0.08 to 0.12 g / cm ³
It is good to If the density is less than 0.06 g / cm ³ , the shape retention is poor due to insufficient strength such as rigidity, and the density is 0.24.
When it exceeds g / cm ³ , the buffering property and the heat insulating property are deteriorated. The expansion ratio corresponding to a density of 0.06 to 0.24 g / cm ³ is 5 to 20 times, and a density of 0.08 to 0.12 g / cm ^3.
The expansion ratio corresponding to is 10 to 15 times. The maximum diameter of the bubbles formed in the foamed sheet is the largest among the diameters of the individual bubbles in the foamed sheet as shown in FIG. And, the average value of the maximum diameter of the bubbles in the foam sheet used in the present invention is 0.1 to 0.7 mm, preferably 0.1.
When the average value is less than 0.1 mm, drawdown occurs during thermoforming, and insufficient cooling is achieved during extrusion foaming, so that only the closed cell ratio is low. On the other hand, when the average value exceeds 0.7 mm, the flexibility and the appearance deteriorate.

Since the polycarbonate resin extruded foamed sheet is thermoformed after lamination to form an automobile interior material, an excellent interior material cannot be obtained unless a foamed sheet having good dimensional stability is used as a raw material during thermoforming. However, in a conventional polycarbonate resin extruded foam sheet, since the melt tension of the base resin is small, it is difficult to pull the sheet sufficiently during extrusion foaming. However, there is a problem that the sheet expands in the extrusion direction, and therefore the dimensional stability is deteriorated, the foamed sheet is easily broken or corrugated during thermoforming, and the yield of excellent molded products is poor. In addition,
The polycarbonate resin foamed sheet is a foamed sheet having high heat resistance as well as good mechanical and electrical properties, but its poor thermoformability has not been used for high-grade molded products. It can be said that the present inventors have succeeded in developing a polycarbonate resin extruded foam sheet having good thermoformability, which makes it possible to manufacture an automobile interior material made of a polycarbonate resin at a low price. Therefore, a polycarbonate resin extruded foam sheet having good thermal stability, which has been found by the present inventors, will be described.

In order to explain the features of the polycarbonate resin extruded foam sheet, a general method for producing an extruded foam sheet will be described below. A resin and an additive such as a bubble control agent are charged in an extruder and heated, melted and kneaded in the extruder. A desired amount of foaming agent is pressed into the kneaded product and the foaming agent is kneaded into the kneaded product. The kneaded product is extruded from the circular die at the tip of the extruder to a low pressure part at a predetermined temperature, and the kneaded product is taken on the cylindrical side surface of a cylindrical resin cooling device (mandrel) to form a tubular foam, and then in the extruding direction. Cut open to form a sheet-like foam. When producing a foamed sheet by the above method, when producing a general resin foamed sheet such as a polystyrene resin foamed sheet,
Since the tubular foam is taken off at a speed slightly higher than the resin extruding speed, tension in the take-out direction is applied to the tubular foam to form flat cells in the cross section in the extruding direction in the foam. Then, when the sheet is heated and softened in a molding machine to form the sheet, the sheet shrinks and becomes tense as the bubbles in the sheet try to change from flat to spherical. As a result, it is considered that a molded product with good shape without heating unevenness can be obtained, and bending strength and mechanical strength are also improved.

On the other hand, in the case of a polycarbonate resin extruded foam sheet, since the resin extruded from the die outlet has a very small elongation, it is difficult to take it into the mandrel at a speed higher than the speed of extruding the resin from the die.
Therefore, in reality, the tubular foam is taken up by the mandrel while being slightly blunted, and the tubular foam is blunted near the die exit where bubbles are formed. Becomes spherical. Since the bubbles are formed in this manner, when the foamed sheet is heated and softened in the molding machine to be molded, the bubbles tend to be spherical at the softening temperature, and the foamed sheet expands. However, since the edge of the sheet is pressed inside the molding machine, there is no escape area for the stretched sheet, and the sheet is wavy in the molding machine and uneven heating occurs, and pucking or tearing occurs when molding such a sheet. However, the quality of the molded product deteriorates. The naki mentioned above means that the skin layer formed on the surface of the foamed sheet has cracks.

In addition to the above, in the conventional production of a polycarbonate resin extruded foam sheet, one of the drawbacks is that it is difficult to produce a foam sheet having a sheet width of 500 mm or more.
This is a problem that occurs because it is difficult to smoothly take out the extruded tubular foam with a mandrel having a diameter that is about 250% or more larger than the circular die diameter because the elongation of the tubular foam is small. If the seat width is narrow, it becomes difficult to use it as an automobile interior material, especially as a ceiling material. In addition, the normal continuous thermoforming machine is designed to use a sheet with a width of at least 500 mm for the purpose of use.
Therefore, the type of molding machine that can be used for a sheet having a width of less than 500 mm is limited. In order to solve these, for example, even if a method of forcibly pulling the tubular foam with a large-diameter mandrel is adopted, in this method there is a problem that the sheet is torn or the sheet thickness becomes thin or the surface condition becomes poor. As a result, high quality foamed sheets cannot be obtained. Therefore, it was attempted to increase the diameter of the circular die to obtain a wide sheet, but in this case it was difficult to maintain the die pressure at the tip of the extruder because the circular die diameter was large, and for that reason the inside of the die Then, the foaming phenomenon occurs, and the quality of the obtained foamed sheet such as the surface condition and mechanical properties is deteriorated.

The polycarbonate resin extruded foamed sheet core material developed by the present inventors has good dimensional stability during molding under heating, so that the sheet is not broken or corrugated, and high-quality molded products can be produced with good yield. It is a foam sheet core material that can be produced, and is an excellent foam sheet having a width of 500 mm or more. X is an average cell diameter (mm) in a direction orthogonal to the thickness direction of the sheet width direction cross section, Y is an average cell diameter (mm) in a direction orthogonal to the thickness direction of the sheet extrusion direction section,
When Z is the average cell diameter (mm) in the thickness direction of the sheet cross section, 1 <X / Z ≦ 3, preferably 1.5 <X / Z ≦ 3
Thus, the foamed sheet is formed of cells having a shape of 1 <Y / Z ≦ 5, preferably 1.5 <Y / Z ≦ 5. Also,
The foamed sheet has an average maximum diameter of bubbles of 0.1 to 0.7 mm, preferably 0.15 to 0.5 mm. This foam sheet is shown in FIG. 2, (a) is a perspective view of the foam sheet, (b) is an enlarged cross-sectional view of the portion indicated by A in (a),
(C) is an enlarged sectional view of a portion indicated by B in (a). Note that X, Y, and Z in FIG. 2 are the sheet width direction,
Sheet extrusion direction and sheet thickness direction, X ₁ ,
X ₂ , Y ₁ , Y ₂ , Z ₁ , and Z ₂ represent the diameter of each bubble in each direction.

Since the air bubbles are formed in the foam sheet core material, the automobile interior material molding base material of the present invention in which a film, a woven fabric or a non-woven fabric is laminated on the core material is 6
Dimensional change during heating for 0 seconds is 0 to -3 in the resin extrusion direction.
It is 0%, particularly -3 to -30%, and since the sheet does not stretch during heat molding, drawdown and corrugation of the sheet do not occur, and a molded product with good heating and uniform heating can be obtained. In addition,
The dimensional change in the width direction under the above heating conditions is -1 to -10.
%, Particularly preferably -3 to -7%. The polycarbonate resin extruded foam sheet developed by the present inventors, which has been described in detail above, can be manufactured by various methods.
For example, the raw material polycarbonate resin has a viscosity average molecular weight of 25,000 or more and a melt tension at 250 ° C. of 2.3.
It is achievable by using more than g. As such a polycarbonate resin, Iupilon S-1000 manufactured by Mitsubishi Gas Chemical Co., Inc. [viscosity average molecular weight 2.6
10,000, melt tension 2.4g (250 ° C)], Iupilon E-
1000 [viscosity average molecular weight 32,000, melt tension 6.4 g
(250 ° C.)], Iupilon E-2000 [viscosity average molecular weight 29,000, melt tension 2.63 g (250 ° C.)] and the like. In addition, it may be achievable by combining a polycarbonate resin other than the above with a specific foaming agent.

In addition to the above, the foamed sheet can be obtained by controlling the temperature of the resin discharged from the extruder or by improving the method for taking up the tubular foam. That is, it is as follows. Generally, a tubular foam extruded from the die tip of an extruder to a low pressure region is inflated by air from the inside to form a balloon (a portion where the diameter of the tubular foam is expanded from the die diameter to the mandrel diameter), and then the mandrel. On the side of the cylinder. When the polystyrene-based resin foam or the polyethylene-based resin foam is produced, the air of the compressor at room temperature may be used as the air, but the base resin for the foamed sheet core material used as the molding base material of the present invention. Is a polycarbonate resin, and its glass transition temperature is as high as 150 ° C., so that the tubular foam solidifies immediately in the air of the compressor at room temperature and the take-up operation becomes difficult. However, if the temperature of the air is adjusted within the range of 51 to 200 ° C., the take-up operation can be facilitated. Further, when the take-up speed is slow during the take-up operation, the orientation in the extrusion direction of the bubbles constituting the foam sheet core material becomes insufficient, so the take-up speed is preferably higher than the speed obtained by the following formula, As a result, a good polycarbonate resin extruded foam sheet core material can be obtained.

(Equation 1)

The polycarbonate resin extruded foam sheet constituting the automobile interior material molding base material of the present invention has a viscosity average molecular weight of 20,000 or more, preferably 25,000 or more, more preferably 30,000 or more. It is desirable to use If the molecular weight is less than 20,000, the molten resin cannot be given a sufficient melt viscosity during the production of the foamed sheet, so that the bubbles are often connected.
Polycarbonate is a polyester formed from carbonic acid, glycol, and bisphenol, and has high crystallinity when the molecular chain contains diphenylalkane, and therefore has high melting point, high heat resistance, and high weather resistance and acid resistance. Become. Examples of such a polycarbonate suitable for the substrate of the present invention include 2,2-bis (4-oxyphenyl) propane (also known as bisphenol A) and 2,2-bis (4-
Examples include bisphenol-based polycarbonates such as oxyphenyl) butane, 1,1-bis (4-oxyphenyl) cyclohexane, 1,1-bis (4-oxyphenyl) isobutane, and 1,1-bis (4-oxyphenyl) ethane. To be done.

In the production of the foamed sheet, all of an inorganic foaming agent, a volatile foaming agent and a decomposable foaming agent can be used. However, if a decomposable foaming agent is used during extrusion foaming, the expansion ratio is high. Since it does not occur, it is preferable to use an inorganic foaming agent or a volatile foaming agent. Carbon dioxide, air, nitrogen and the like are preferably used as the inorganic foaming agent. Examples of volatile blowing agents include propane, n-butane, i-butane, n-
Lower aliphatic hydrocarbons such as pentane, i-pentane and n-hexane; lower alicyclic hydrocarbons such as cyclobutane and cyclopentane; lower aromatic hydrocarbons such as benzene, toluene and xylene; aliphatic such as methanol and ethanol Lower monohydric alcohol; lower aliphatic ketone such as acetone and methyl ethyl ketone; low boiling point such as 1-chloro-1,1-difluoroethane, pentafluoroethane, 1,1,1,2-tetrafluoroethane and 1,1-difluoroethane Halogenated hydrocarbons and the like are exemplified.

The above-mentioned foaming agents can be used alone or as a mixture of two or more kinds, and it is also possible to use different types of foaming agents such as an inorganic foaming agent and a volatile foaming agent in combination. The amount of the foaming agent used varies depending on the type of the foaming agent and the desired expansion ratio, and the density of the foamed sheet is determined by the expansion ratio. Therefore, it can be said that the amount of the foaming agent used is mainly determined by the desired density of the foamed sheet. In the present invention, since a foamed sheet having a density of 0.06 to 0.24 g / cm ³ is used, the amount of the foaming agent used per 100 parts by weight of the resin corresponding to the density is 0. 5-10 parts by weight (when butane is used), 0.2-for inorganic blowing agents
It is sufficient to use about 3.0 parts by weight (when using carbon dioxide).

In the foamed sheet used in the present invention, in order to smoothly foam the polycarbonate resin, a cell regulator may be added to the melt-kneaded product of the resin and the foaming agent, if necessary. In this case, the air bubble modifier is preferably an inorganic powder such as talc or silica, an acid salt of polyvalent carboxylic acid, a mixture of polyvalent carboxylic acid and sodium carbonate or sodium bicarbonate, and the like. The addition amount is 0.01 to 1.0 part by weight, preferably 0.05 to 100 parts by weight, based on 100 parts by weight of the resin.
0.5 parts by weight is preferable. In addition, the foam sheet,
Like flame retardants, heat stabilizers, weather resistance improvers, colorants, etc.
Known additives that are added to ordinary foamed sheets can be added.

As described above, the foamed sheet used as the base material for molding an automobile interior material of the present invention has a relationship between a melt viscosity of a raw material resin and a viscosity average molecular weight, a method of collecting an extruded tubular foamed body, and the like. Note that the tubular foam can be drawn onto a mandrel having a diameter of 250% or more, and even 300-350% of the circular die diameter. Then, even if the tubular foam is taken into a mandrel having a diameter larger than the circular die diameter by 250% or more, the thickness of the sheet does not become thin partially or entirely, and the desired thickness of the sheet is 2 to 8 mm. can do. Also,
To make the thickness of the sheet more uniform, narrow the resin channel width near the opening of the circular die; from the surface of the mandrel and the outside when the tubular foam extruded from the circular die is taken into the mandrel and cooled. The inner surface and the outer surface of the tubular foam may be blown with cooling air;

In the case of producing the base material of the present invention, the polycarbonate resin which is the base resin of the film has a relatively low molecular weight of a viscosity average molecular weight of 10,000 or more and less than 20,000, preferably 14,000 to 18,000. Polycarbonate resin is used. The reason why the low molecular weight polycarbonate resin is preferably used is as follows. Since foaming is unnecessary, it is not necessary to increase the melt viscosity. In order to produce a film having a uniform thickness by extruding from a T-die, it is preferable to use a low molecular weight polycarbonate resin having a good flow as a raw material. When laminating a polycarbonate resin extruded foam sheet and a polycarbonate resin film, it is possible to integrally manufacture by a coextrusion laminating method, an extrusion laminating method, etc., but in this case, the bubbles of the foam sheet surface layer are high temperature resin for the film. Be careful not to destroy it. Therefore, when extrusion-laminating to a foam sheet with a T-die, it is desirable that the melting point of the base resin of the foam sheet is higher than that of the base material of the film. Therefore, the viscosity average molecular weight of the foam sheet base resin is It is desirable to make it larger than that.

The polycarbonate resin film used as the base material of the present invention is a polycarbonate resin film having a thickness of 0.1 to 0.3 mm, preferably 0.15 to 0.25 mm. If the thickness is less than 0.1 mm, the shape retention is deteriorated and the moldability is poor, so that it becomes difficult to form an interior material having a complicated shape. Further, if the thickness exceeds 0.3 mm, it becomes difficult to stack the foamed sheets, and thus the stacking efficiency decreases. Other resins may be mixed with the polycarbonate resin film as long as the adhesiveness with the foamed sheet is not impaired. That is, a polyester resin, various polystyrene resins, or the like can be used as a mixture with the polycarbonate resin, and the amount of the mixture is 40% by weight or less, preferably 20% by weight or less of the total amount of the resin. The above polycarbonate resin film may be laminated on both sides of the foamed sheet by a known method such as an extrusion laminating method (extrusion laminating), a thermal laminating method (thermal laminating), a laminating method using a hot melt adhesive or the like. Thus, a laminate suitable as a base material for molding automobile interior materials can be obtained.

The woven or non-woven fabric made of fiber used as the base material of the present invention has a thickness of 0.1 to 1 mm, preferably 0.2 to 0.5.
If the thickness is less than 0.1 mm, the strength tends to be insufficient, and if the thickness exceeds 1 mm, the elongation is poor and the thermoforming becomes difficult. Examples of the base fibers of the fiber woven fabric used here include polyester fibers such as polyethylene terephthalate, polyolefin fibers such as polypropylene, inorganic fibers such as glass, pulp fibers and the like. Of these, glass fiber is preferable, and the glass may be soft, hard, or special glass such as quartz glass, but has a basis weight of 50 to 50.
600 g / m ^2, preferably it is desirable that the 150 to 300 g / m ^2. Many such glass fiber woven fabrics are commercially available, for example, HS-1 manufactured by Asahi Fiber Glass Co., Ltd.
You can use 80 etc. Similarly, the non-woven fabric made of fiber is not limited to the kind of fiber or the manufacturing method, and the basis weight is 50 to 600 g /
m ² and preferably 150 to 450 g / m ² may be used. It should be noted that the same fiber as the fiber woven cloth may be used as the non-woven fabric substrate, and glass fiber is preferred. Also in this case, since many products are commercially available, CM-300 or CM-400 manufactured by Asahi Fiber Glass Co., Ltd. may be used.
Lamination of the woven or non-woven fabric made of fibers and the foamed sheet may be carried out by a known method such as a method using a hot melt adhesive or a method using a molten polycarbonate resin as an adhesive, on both sides or one side of the foamed sheet. Just stack them.

The automobile interior material molding base material of the present invention is obtained by laminating a polycarbonate resin film on both sides of a polycarbonate resin extruded foam sheet as described above, or by using a woven fabric or a non-woven fabric of a fiber in at least one of the foam sheets. It is a substrate manufactured by laminating the surface as described above. Then, various forming methods of the base material include vacuum forming method and pressure forming method, for example, free drawing forming method, plug-and-ridge forming method, ridge forming method, matched mold forming method, straight forming method, drape. Molding method, reverse draw molding method, air slip molding method,
It can be molded into a desired shape by a plug assist molding method, a plug assist reverse draw molding method, a molding method in which these are combined, or the like to obtain an automobile interior material. The automobile interior material molding base material of the present invention is a door trim,
Molded into ceiling materials, instrument panels, engine room partitioning materials, trunk room flooring materials, etc. Among them, it is particularly preferable to use as a base material for molding a ceiling material because the characteristics of the base material can be sufficiently exhibited.

[0026]

EXAMPLES Next, the present invention will be described more specifically by way of examples, but the present invention is not limited to these examples. The parts shown below are parts by weight.

Examples 1 to 4 and Comparative Examples 1 to 3 (Extruded Foamed Sheet) The automobile interior material molding base material of the examples is a laminate having a polycarbonate resin extruded foamed sheet as a core material. For the polycarbonate resin used as the raw material, Iupilon (E-2 manufactured by Mitsubishi Gas Chemical Co., Inc.
000 or S-3000) was used. Further, as the base resin of the foamed sheet of the comparative example, polyphenylene ether (PPE) modified polystyrene resin (manufactured by Mitsubishi Gas Chemical Co., Ltd .;
Product name: Iupiace THUH25, THUH30),
Alternatively, a maleic anhydride-modified polystyrene resin (manufactured by Arco Chemical Co .; Dailark # 232) was used. With respect to the foamed sheet base resins used in Examples and Comparative Examples, Table 1 shows the names, compositions, and special notes such as viscosity average molecular weight (Wv) and heat deflection temperature (HDT). The HDT is the temperature (° C.) when a sample under a load of 18.5 kg / cm ² is bent by 0.254 mm, and A
It is the heat deflection temperature specified in STM D-648.

The extruded foam sheets used in the examples and comparative examples were prepared by adding 0.05 part of talc as a cell adjuster to 100 parts of the resin and kneading the mixture well, and then extruding a foaming agent of the type and amount shown in Table 2. 20 after press-fitting and kneading
It is a foamed sheet produced by extruding from a circular die at a temperature of about 0 ° C., and has a good thermoformability similar to a polystyrene resin extruded foamed sheet. Table 3 shows the density, width, thickness, average value of the maximum bubble diameters, and bubble shape of this foam sheet. In addition, X, Y described in Table 3,
Z is a symbol having the same meaning as described above for explaining the bubble shape, X is the average bubble diameter (mm) in the direction orthogonal to the thickness direction of the sheet width direction cross section, and Y is the sheet extrusion direction cross section thickness direction. Average bubble diameter (m
m) and Z are average cell diameters (mm) in the thickness direction of the sheet cross section.
Is represented. Further, as shown in FIG. 1, the maximum diameter of bubbles is the maximum diameter of bubbles measured in the sheet width direction and the cross section in the extrusion direction, and the maximum diameter is measured for at least 100 bubbles from each cross section, and the average thereof is obtained. The calculated value is the average value of the maximum diameters. Also, the number of bubbles (cells / mm)
Is a value obtained by dividing the number of bubbles in a straight line drawn in the thickness direction in the width direction or the extrusion direction cross section of the foamed sheet by the thickness, and rounding off to the nearest whole number.

(Material to be Laminated on Foamed Sheet and Laminating Method) The automobile interior material molding base materials of Examples and Comparative Examples are laminates in which a resin film or a fibrous nonwoven fabric is laminated on both sides of the foamed sheet. A resin of the same type as the base resin of the foamed sheet was used as the resin film for the body in order to enhance the adhesiveness, and the resin film was laminated on both sides of the foamed sheet by the extrusion laminating method. Table 4 shows the type and thickness of the resin film used.
Note. The resin for film used in Comparative Examples 1 and 2 is PPE-modified polystyrene resin. Further, as can be seen from Table 4, the base material for molding the interior material of Example 4 is a base material in which a glass fiber non-woven fabric is laminated on both sides of the foam sheet, and the glass fiber non-woven fabric is manufactured by Asahi Fiber Glass Co., Ltd. CM-
300, average length of single fiber 50 mm, thickness 0.3
mm, basis weight 300 g / m ² Non-woven fabric. The resins shown in Table 4 were used for the resin film used for lamination on the foamed sheet. That is, the resin was supplied to an extruder and extruded in a molten state from a T die to form a film, which was in-line laminated on both sides of a foamed sheet by an extrusion laminating method. Two series of T dies were used to laminate the film on both sides of the foamed sheet. Further, the clearance of the nip roll for pressing the laminated sheet completely to press it was 80% of the laminated sheet thickness.

[0030]

[Table 1]

[0031]

[Table 2]

[0032]

[Table 3]

[0033]

[Table 4]

Table 5 shows temperatures when the foamed sheet and the film are laminated by the extrusion laminating method. In the production of the substrate of Example 4 in which glass fiber nonwoven fabrics were laminated, Iupilon H-4000 was laminated at the indicated temperature as an adhesive. Table 5 also shows the density and thickness of the foam sheet core material, the thickness of the film, and the density and thickness of the obtained laminate (base material).

[0035]

[Table 5]

Comparative Example 4 A 0.7 mm thick Iupilon E-2000 film was used.
Cut into 00 mm squares, and the carbon dioxide pressure is 40 kg / c
After leaving it in a pressure vessel kept at m ² for 60 hours at 23 ° C., it was heated for 40 seconds in an oil bath kept at 160 ° C. for foaming. Due to this foaming, the thickness becomes 1.8 mm,
Weight increased by 7%. On this foamed sheet, Iupilon H-4000 having a thickness of 0.2 mm manufactured as described above.
The film was laminated by an extrusion laminating method with a T-die to obtain a sample of Comparative Example 4. In Comparative Example 4, both the method for producing the foamed sheet and the sample form are different from the others, but for comparison, the data of Examples and Comparative Examples shown in Tables 1 to 6 are also shown together with the data of Comparative Example 4. did.

Comparative Example 5 Iuplon H-4000 was added with 3.8% by weight of isopentane as a foaming agent, and an extruded foam sheet was produced in the same manner as in Example 1, but it could not be produced. .

(Evaluation Method) The base material manufactured as described above was molded by using a headliner molding die to obtain an automobile interior ceiling material. In order to examine the superiority or inferiority of this ceiling material, Table 6 shows the results of evaluation of punching workability and heating dimensional change at 85 ° C and 170 ° C. The various evaluations were performed as follows. Punching workability: Equilateral triangle samples are punched from 10 end parts of automobile interior materials so that the length of one side is 1 cm. ○, 1 or 2 places when all 10 parts are punched correctly The case where a defect or damage was observed by punching was shown as Δ, and the case where a defect or damage was observed at 3 or more places was expressed as x. The punching was performed by pressing with a Thomson blade.

Heating dimensional change at 85 ° C .: 220 × 2
A 20 mm test piece is prepared, and a straight line having a length of 100 mm in the flow direction (MD) and the width direction (TD) is drawn in a cross shape in the central portion thereof. The test piece was placed in an oven at 85 ± 2 ° C for 24 hours.
After the heat treatment for a time, the length of the straight line is measured, and the change in heating dimension is obtained by the following formula. Change in heating dimension = [(length after heating mm-100 mm) / 10
0 mm] × 100 This test is performed 3 times (n = 3), and the average value is taken as the change in heating dimension in the MD and TD directions. Then, the range where the change is −0.2% to + 0.2% is regarded as a pass. The change in the heating dimension in the thickness direction is obtained by obtaining the change in the heating dimension as described above from the change in the thickness before and after the heat treatment by the above method, and performing this five times (n = 5) to obtain the average value in the thickness direction. Change in dimension is accepted, and in this case, a change in thickness within 20% is regarded as acceptable. In Table 6, from the results obtained as described above, "pass" is indicated by "o" and fail is indicated by "x". Change in heating dimension at 170 ° C .: A test piece of 150 × 150 mm is prepared, and a straight line having a length of 100 mm in the MD direction and the TD direction is drawn in a cross shape in the central portion thereof. The test piece was heat-treated in an oven at 170 ± 2 ° C. for 60 seconds, and then the length of the straight line was measured.
It is determined in the same manner as in the case of a change in heating dimension at 5 ° C.

[0040]

[Table 6]

As can be seen from the comprehensive evaluation shown in Table 6,
The automobile interior materials of Examples in which a polycarbonate resin is used as a raw material for an extruded foamed sheet have good heat dimensional stability and punching workability, but Comparative Examples 1 to 3 in which a modified polystyrene resin is used as a raw material for the foamed sheet. Those having poor heating dimensional stability and punching workability cannot be said to be good automobile interior materials. Further, the foamed sheet obtained by impregnating and foaming carbon dioxide gas of Comparative Example 4 was 6 at 170 ° C.
Drawdown was observed when heated for 0 seconds, and moldability was not good.

[0042]

The base material for molding automobile interior materials according to claims 1 and 2 is a laminated body having a core material of a polycarbonate resin foam sheet having a specific density and an average value of the maximum diameters of the specified cells. An automobile interior material such as a ceiling material produced by heat molding is lightweight but has high mechanical strength and thermal strength. Therefore, the interior material such as the ceiling material does not cause dimensional shrinkage or the like even when the temperature inside the automobile becomes high in the summer and the like, and the "waffle" is generated during the punching process when manufacturing the interior material from the base material.
It is an automobile interior material that can be provided at a low price in addition to the extremely low occurrence of "breakage". Therefore, it is most suitable as a base material for molding automobile interior materials, which requires heat resistance and is often punched. The automobile interior material molding base material according to claim 3 is an interior material base material having a large number of closed cells, since it has good foaming properties and bubbles are less likely to collapse when the foamed sheet and the film are laminated. Therefore, when an interior material is manufactured using the base material, the heat insulation is high and the thermal strength can be further enhanced. The automobile interior material molding base material according to claim 4 has good dimensional stability during heat molding because the bubbles forming the foamed sheet have a specific shape. It is a base material for forming an interior material, which can improve the yield when producing the interior material.

[Brief description of drawings]

FIG. 1 is a diagram illustrating the maximum diameter of bubbles formed in a foam sheet used in the present invention.

FIG. 2 is a diagram illustrating the shape of bubbles formed in the foam sheet used in the present invention.

[Explanation of symbols]

 X sheet width direction Y sheet extrusion direction Z sheet thickness direction

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location B29L 31:58

Claims (6)

[Claims] 1. A density of 0.06 to 0.24 g / cm ³ , an average maximum bubble diameter of 0.1 to 0.7 mm, and a thickness of 2 to 8 m.
A substrate for molding an automobile interior material, comprising a polycarbonate resin extruded foam sheet of m as a core material, and a polycarbonate resin film laminated on both surfaces of the foam sheet. 2. A density of 0.06 to 0.24 g / cm ³ , an average maximum bubble diameter of 0.1 to 0.7 mm, and a thickness of 2 to 8 m.
A substrate for molding an automobile interior material, comprising a polycarbonate resin extruded foam sheet of m as a core material, and a woven or non-woven fabric made of fibers laminated on at least one surface of the foam sheet. 3. The base resin of the foamed sheet is a polycarbonate resin having a viscosity average molecular weight of 20,000 or more, and the base resin of the film is a polycarbonate resin having a viscosity average molecular weight of less than 20,000. A base material for molding automobile interior materials. 4. The automobile interior material molding base material according to claim 1, wherein the cell shape is formed so as to satisfy the following conditional expression. 1 <X / Z ≦ 3 1 <Y / Z ≦ 5 [where X is the average cell diameter (mm) in the direction orthogonal to the thickness direction of the sheet width direction cross section, and Y is orthogonal to the thickness direction of the sheet extrusion direction cross section] The average bubble diameter (mm) in the direction
Z represents the average cell diameter (mm) in the thickness direction of the sheet cross section] 5. The automobile interior according to claim 1, wherein the dimensional change when heated at 170 ° C. for 60 seconds is in the range of 0 to −30% in the resin extruding direction. Base material for forming materials. 6. The base material for molding an automobile interior material according to claim 1, wherein the base material for forming an automobile interior material is for molding a ceiling material.