JPH08230114A - Paper machine-made stampable sheet, lightweight stampable sheet molding and lightweight stampable sheet skin-laminated product - Google Patents

Abstract

PURPOSE: To obtain excellent adhesiveness and non-air permeability by laminating and heat crimping films A, B which are composed of a resin which has a structure identical or similar to that of a thermoplastic resin forming a web and has a melting point or a melt viscosity equal to or higher than that of the thermoplastic resin, and a resin with a low melting point with the film A positioned on the web side. CONSTITUTION: A dense paper machine-made stampable sheet is made integrally by laminating and heat crimping films A, B to a sheet web 1 obtained by paper machine-making a mixture of a thermoplastic resin and reinforced fibers with the film A, positioned on the web side. As a resin to form the film A, one having a structure identical or similar to that of the thermoplastic resin forming the web and a melting point or melt viscosity equal to or surpassing that of the thermoplastic resin is used. As a resin to form the film B, one having a structure identical to or similar to that of the thermoplastic resin forming the web and having a low melting point is used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet-forming stampable sheet excellent in adhesiveness and non-breathability, and a light-weight stampable sheet molded product and a light-weight stampable sheet-covered product produced from this sheet. Yes, especially,
The light-weight stampable sheet skin-attached product has excellent adhesion between the base material and the skin and has improved non-air permeability, and is useful as an automobile interior product such as a ceiling material or a door trim material.

[0002]

2. Description of the Related Art Stampable sheets mainly composed of reinforcing fibers and thermoplastic resins can be molded into complicated shapes, and the molded products have high strength and are lightweight in recent years. It is drawing attention as a substitute for products. Such a stampable sheet is manufactured by applying a papermaking technique, for example, by the following method. That is, first, a sheet-shaped web (deposit) is prepared by making a dispersion liquid in which a granular thermoplastic resin and reinforcing fibers are dispersed in a surfactant aqueous solution containing microbubbles on a porous support. Then, after heating the web once to a temperature not lower than the melting point and lower than the decomposition point of the thermoplastic resin,
By pressurizing and cooling, a dense solidified sheet, a so-called sheet-forming stampable sheet, is obtained.

[0003] This stamping sheet made by the papermaking method contains reinforcing fibers which have been opened to a substantially single fiber state. Therefore, when heated again to a temperature above the melting point of the resin and below the decomposition point,
The fibers restrained by the resin cause springback, and become an expanded sheet that has expanded several times or more than the original thickness.
Then, the expanded sheet is subjected to compression molding, vacuum molding, pressure molding, etc., to enable molding of a lightweight stampable sheet having a predetermined shape. That is, the mold clearance at the time of molding is the theoretical thickness (thickness when the porosity of the product is zero)
By making a larger adjustment, it is possible to obtain a porous lightweight stampable sheet molded article having a density smaller than that of the above-mentioned papermaking method stampable sheet and high surface rigidity. Such a light-weight stampable sheet molded article and its manufacturing method have been proposed, for example, in JP-A-60-179234 and JP-A-62-161529. When the light-weight stampable sheet molded product is used for a part requiring decorativeness, it is generally a light-weight stampable sheet skin-bonded product obtained by bonding the expansion sheet and the decorative skin. Target.

As such a light-weight stampable sheet skin laminated product, conventionally, there is one in which the expansion sheet and the decorative skin are simply laminated by heat-pressing without an adhesive. However, it is not possible to expect sufficient adhesion strength between the light-weight stampable sheet (hereinafter simply referred to as "base material") and the epidermis in a simple epidermis bonding without an adhesive layer between the sheet and the epidermis. The reason is that the contact area between the expansion sheet and the skin with a large porosity is small,
Moreover, the adhesive component at the time of bonding is only the thermoplastic resin present in the surface layer of the expansion sheet. Also, since the lightweight stampable sheet skin-bonded product is molded while maintaining the expanded state of the expansion sheet, the molding pressure at the time of bonding is small. Therefore, the penetration of the resin component from the inside of the expansion sheet to the surface (supply ) Is also small.

In view of these circumstances, in recent years, there has been proposed a light-weight stampable sheet skin-bonded product in which an adhesive layer is interposed between a base material and a skin to be integrated. For example: A technique for improving the adhesion between the base material and the surface skin by pressure-molding with a hot melt type adhesive film interposed between the base material and the surface skin (see JP-A-5-16274); A technology to improve the adhesion between the base material and the epidermis and prevent the resin from seeping out to the epidermis surface by pressure molding with a thermoplastic resin containing an inorganic filler interposed between the base material and the epidermis. (See Japanese Patent Laid-Open No. 4-331137) ,. A technique for improving the adhesiveness between the base material and the skin and the appearance on the skin side by pressure-molding the skin laminated with the porous sheet of thermoplastic resin and the expansion sheet (JP-A-5-16277). (See), is proposed.

However, the techniques according to the various proposals described above have the following problems. That is ,. In the technology of pressure molding with a hot melt type adhesive film interposed between the base material and the skin, the fluidity of the adhesive film increases during pressure molding, and the porous light weight material that is the base material is used. It penetrates into the voids of the stampable sheet, forms a so-called effective adhesive impregnated layer, and does not remain between the substrate and the skin. Therefore, there is a problem that the adhesion between the base material and the epidermis is not sufficient, and the non-air permeability is poor. That is, with such a material having poor air permeability,
The required amount of pressure loss cannot be secured in the pasting composite type (especially vacuum forming), condensation is likely to occur between the member to which the skin-bonded product is attached and corrosion of the member is easily caused, and the skin-bonded product as a filter. There is a possibility that it may act and cause problems such as soiling of the epidermis. Therefore, it is important to improve the above-mentioned non-permeability of the lightweight stampable sheet skin-bonded product useful as an automobile interior product such as a ceiling material or a door trim material. ． In the technology of pressure molding in which a thermoplastic resin containing an inorganic filler is interposed between the base material and the skin, the filling amount of the inorganic filler is adjusted to improve the appearance (resin bleeding) and adhesion. Although it can be improved to some extent, there is a problem that it is difficult to improve both adhesion and non-air permeability. ． In the technique of press-molding the surface layer and the expansion sheet on which the thermoplastic resin porous sheet is laminated, the fluidity of the thermoplastic resin porous sheet is poor, and the contact area between the porous sheet and the expansion sheet is also small. There was a problem that the anchor effect of the porous sheet was not sufficiently exhibited and the adhesion between the base material and the epidermis was poor.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and in particular, a paper-making stampable sheet excellent in adhesiveness and non-breathing property has been developed. It is an object to provide an improved lightweight stampable sheet molded article and a lightweight stampable sheet skin-bonded article having excellent adhesion between a base material and a skin and improved non-air permeability.

[0008]

Means for Solving the Problems As a result of intensive studies aimed at achieving the above-mentioned objects, the inventors have found that when a thermoplastic resin and a reinforcing fiber are formed into a sheet by paper-forming, the adhesiveness and the It has been found that by laminating a film having both non-breathability, it is possible to improve both the adhesiveness and non-breathability of the stampable sheet made by the papermaking method. Furthermore, by using this paper-making stampable sheet, the film remains as a continuous layer between the base material and the epidermis even after the epidermis is laminated, and an impregnated adhesive layer having a sufficient thickness is provided on the base material surface side. It was found that the adhesion and the non-air permeability of the light-weight stampable sheet skin-bonded product can be improved by forming the invention, and the present invention has been completed.

That is, the present invention relates to (1) a paper-making stampable sheet obtained by heat-pressing and solidifying a sheet-shaped web obtained by paper-forming a mixture of a thermoplastic resin and reinforcing fibers, wherein A film A made of a resin having the same or similar structure as that of the thermoplastic resin and having a melting point or a melt viscosity similar to or higher than that of the thermoplastic resin, and the thermoplastic resin constituting the web. And a film B having a structure similar to or similar to the above and a film B made of a resin having a melting point lower than that of the thermoplastic resin are laminated so that the film A is located on the web side, It is a dense sheet-forming stampable sheet that is integrated. (2) In the invention described in (1) above, polypropylene having a melting point of 135 ° C. or higher is used as the thermoplastic resin forming the web, and the resin forming the film A is
Polypropylene having the same or similar structure as the thermoplastic resin and a melting point of 135 ° C. or higher is used, and the resin constituting the film B has the same or similar structure as the thermoplastic resin, and It is a stampable sheet made by a papermaking method, characterized in that polypropylene or polyethylene having a lower melting point than a thermoplastic resin is used. (3) In the invention described in (1) above, there is provided a papermaking method stampable sheet characterized in that the film A is filled with a filler. (4) In the invention described in (1) above, polypropylene is used as the thermoplastic resin forming the web, and the resin forming the film A has the same or similar structure as the thermoplastic resin, and The film B is made of polypropylene having a melt viscosity equal to or higher than that of the thermoplastic resin by being filled with a filler.
Is a stampable sheet made by a papermaking method, which uses polypropylene having a structure similar to or similar to that of the thermoplastic resin and having a melting point lower than that of the thermoplastic resin as a resin constituting the resin. (5) The sheet-forming stampable sheet according to any one of the above (1) to (4) is expanded by heating to form an expanded sheet, and the expanded sheet has a theoretical density (zero porosity) after molding. It is a lightweight stampable sheet molded article characterized by being formed into a porous body by compression molding so that the density becomes smaller than the (time density). (6) The stamping sheet made by the papermaking method according to any one of (1) to (4) above is expanded by heating to form an expanded sheet, and the expanded sheet and the skin are superposed, and the density after molding is the theoretical density. A light-weight stampable sheet skin-bonded product characterized by being formed into a skin-bonded porous body by compression molding so as to be smaller than (density at zero porosity).

[0010]

The feature of the paper-making stampable sheet according to the present invention is that a two-layer film consisting of a non-breathable film A and an adhesive film B is placed on a paper-making sheet consisting of a thermoplastic resin and reinforcing fibers. It is in the point where it was laminated. Thereby, when the above-mentioned papermaking method stampable sheet is heated and pressed (expansion molded), a porous stampable sheet molded article having excellent air permeability and adhesiveness can be obtained.
In addition, when the above-mentioned papermaking method stampable sheet and the skin are superposed and expansion-molded, the adhesion between the base material and the skin is improved in comparison with the conventional lightweight stampable sheet skin-bonded product with a single adhesive layer interposed. It is possible to obtain a light-weight stampable sheet and skin-bonded product which is excellent and has improved non-air permeability. Here, in the light-weight stampable sheet skin-bonded product,
Since the film A is composed of a resin having a melting point or melt viscosity that is equal to or higher than that of the thermoplastic resin forming the base material, a base material surface side is provided with an impregnated adhesive layer having a sufficient thickness. It remains between the material and the epidermis and acts as a non-breathing layer and also as an adhesion auxiliary layer that improves the adhesion strength due to its anchoring effect. On the other hand, since the film B is made of a resin having a melting point lower than that of the thermoplastic resin forming the base material, the film B melts at the time of sticking the skin and acts as an adhesive layer with the skin.

The structure of the present invention will be described in detail below. The papermaking method stampable sheet of the present invention is a papermaking method stampable sheet obtained by heat-pressing and solidifying a sheet-shaped web obtained by paper-forming a mixture of a thermoplastic resin and reinforcing fibers, to form the web. A film A made of a resin having the same or similar structure as the thermoplastic resin and having a melting point or a melt viscosity equal to or higher than that of the thermoplastic resin, and the same thermoplastic resin as the web. Or have a similar structure,
A dense paper stamping method in which a film made of a resin B having a melting point lower than that of the thermoplastic resin is laminated so that the film B is located on the web side and integrated by thermocompression bonding. It is a sheet. The light-weight stampable sheet molded article of the present invention is an expanded sheet obtained by heating and expanding the above-described papermaking method stampable sheet, and the density of this expanded sheet is smaller than the theoretical density (density when the porosity is zero). A light-weight stampable sheet molded article, characterized in that it is formed into a porous body by compression molding. The light-weight stampable sheet skin-bonded product of the present invention is an expanded sheet obtained by heat-expanding the above-mentioned papermaking method stampable sheet, and by superposing the expanded sheet and the skin, the density after molding is theoretical density (porosity of zero). A light-weight stampable sheet skin-bonded product characterized by being formed into a skin-bonded porous body by compression molding so that the density becomes smaller than the (time density).

[0012] As reinforcing fibers constituting the substrate in the present invention for reinforcing fibers, glass fibers, carbon fibers, boron fibers, inorganic fibers such as other metal fibers or aramid fibers and polyester fibers, polyamide fibers, wood fibers, etc. Organic fibers of can be used. The fiber length of this reinforcing fiber is excellent in the reinforcing effect, and from the viewpoint of ensuring the formability during papermaking molding,
It is desirable that the thickness is in the range of 5 to 30 mm, preferably 10 to 26 mm. The reason for this is that if the fiber length is shorter than 5 mm, a sufficient reinforcing effect cannot be obtained and the paper breaks easily in the papermaking process. On the other hand, when the fiber length exceeds 30 mm, the reinforcing fibers are not sufficiently opened in the papermaking process, the expansion of the molded product becomes uneven, and the spring bag effect is reduced.
As a result, the expandability of the molded article decreases, and at the same time the shapeability during molding deteriorates. The fiber diameter of the reinforcing fiber is preferably in the range of 5 to 30 μm, and more preferably 10 to 25 μm from the viewpoint of ensuring the reinforcing effect and the expansion effect by the fiber. The reason is that if the fiber diameter is smaller than 5 μm, a sufficient expansion ratio cannot be obtained, while the fiber diameter is 30
This is because if it exceeds μm, a sufficient reinforcing effect cannot be obtained.

If necessary, the reinforcing fibers are surface-treated with a coupling agent or a sizing agent. Especially,
In order to improve the wettability and adhesiveness between the reinforcing fiber and the thermoplastic resin, a treatment with a silane coupling agent is performed.
As the silane coupling agent, vinyl silane-based,
It is preferable to use an aminosilane-based, epoxysilane-based, methacrylsilane-based, chlorosilane-based, or mercaptosilane-based coupling agent. Surface treatment of the reinforcing fiber with such a silane coupling agent, a method of spraying a silane coupling agent solution while stirring the reinforcing fiber,
It can be carried out by a known method such as a method of immersing the reinforcing fiber in the coupling agent solution. The treatment amount of the silane coupling agent was 0.001 with respect to the reinforcing fiber.
It is desirable to set the content in the range of 0.3 wt%, preferably 0.005 to 0.2 wt%. The reason for this is that with a treatment amount of less than 0.001 wt%, the improvement in strength is small. Further, in order to improve the strength and expandability of the sheet-forming stampable sheet, it is desirable that the reinforcing fibers be opened into single fibers. Therefore, the reinforcing fiber is optionally treated with a water-soluble sizing agent. Examples of the sizing agent include polyethylene oxide type and polyvinyl alcohol type. The processing amount of this sizing agent is 0.03 to 0.3 wt.
%, Preferably 0.05 to 0.2 wt%. The reason for this is that it is difficult to open the fibers in the papermaking process when the treatment amount exceeds 0.3 wt%.

[0014] The thermoplastic resin as the thermoplastic resin constituting the substrate in this invention, for example, polyolefins such as polyethylene and polypropylene, polystyrene, polyvinyl chloride, polyethylene terephthalate, polycarbonate, polyamide, polyacetal, and these resins Use a copolymer as a main component (for example, an ethylene-vinyl chloride copolymer, an ethylene-vinyl acetate copolymer, a styrene-butacien-acrylonitrile copolymer, etc.), a graft compound, or a blended product of these resins. You can Of these, polypropylene is the most preferable. The weight average molecular weight of the thermoplastic resin (hereinafter, simply referred to as "M _W".) Is preferably in the range of 50,000～700,000. The reason for this is that when M _W is less than 50,000, the melt viscosity is low and the wettability and adhesion to the reinforcing fibers are good, but the resin tends to become brittle, and the mechanical properties of the fiber-reinforced thermoplastic resin base material formed by molding Is reduced. on the other hand,
This is because when M _W exceeds 700,000, the fluidity at the time of papermaking and molding is deteriorated, and the impregnating property and the wettability at the joining point of the reinforcing fibers are deteriorated, and the mechanical properties of the base material are also deteriorated. As the thermoplastic resin, those having a granular shape, a flake shape, a fibrous shape or the like can be used. Particularly in the case of granular particles, it is desirable to use particles having a resin particle size in the range of 50 to 2000 μm. The reason for this is that if the resin particle size is less than 50 μm, problems such as biting into the device are likely to occur during web production, while if the resin particle size exceeds 2000 μm, the fiber-reinforced resin in which the resin is uniformly dispersed in the reinforcing fibers This is because it becomes difficult to obtain a thermoplastic resin substrate.

The thermoplastic resin may be used in combination with a resin modified with various compounds such as acid or epoxy in order to improve the adhesion between the resin and the reinforcing fiber. For example,
In the case of polypropylene, maleic acid or maleic anhydride,
Those which can be modified with acrylic acid or the like and whose modifying group is an acid anhydride group or a carboxyl group are preferred. The modified resin is desirably M _W is in the range of 20,000 to 200,000. The reason for this is that when M _W is less than 20,000, the melt viscosity is low and the wettability and adhesion to the reinforcing fibers are good, but the resin tends to become brittle, and the mechanical properties of the fiber-reinforced thermoplastic resin base material formed by paper forming are Because it will decrease. on the other hand,
When M _W exceeds 200,000, more than with fluidity during papermaking molding is reduced, to deteriorate the impregnation property and wettability of the reinforcing fibers junction, because also the mechanical properties of the base material is lowered. This modified resin contains 0.02 to 3.0 wt% of the modifying group.
(100 × weight of modifying group / weight of thermoplastic resin), preferably in the range of 0.05 to 2.0 wt%. The reason for this is that if the amount of the modifying group is less than 0.02 wt%, the reaction with the silane coupling agent becomes insufficient and the improvement in strength is small. On the other hand, when it exceeds 3.0 wt%, disadvantages such as embrittlement of the thermoplastic resin and coloring of the sheet are caused. When the modified resin is used in combination as the thermoplastic resin, webs made of the respective resins may be laminated and molded to produce a fiber-reinforced thermoplastic resin substrate, and these resins may be melted in advance with an extruder or the like. It is also possible to produce a fiber-reinforced thermoplastic resin base material by subjecting a material obtained by kneading and pulverizing, or a material obtained by coating one resin with another resin, to papermaking molding.

Blending Ratio of Reinforcing Fiber and Thermoplastic Resin The blending ratio of the reinforcing fiber and the thermoplastic resin constituting the substrate in the present invention is 20/80 to 70 / in terms of weight ratio (fiber / resin).
It is desirable to set it within the range of 30. The reason for this is that if the blending ratio (content) of the reinforcing fibers is less than 20 wt%, a sufficient reinforcing effect due to the reinforcing fibers cannot be expected, while if the blending ratio (content) of the reinforcing fibers exceeds 70 wt%, This is because when expanded, the thermoplastic resin as a binder component becomes insufficient, and it becomes difficult to uniformly impregnate the resin to the reinforced fiber bonding points, resulting in a decrease in strength.

Skins As the decorative skins constituting the light-weight stampable sheet skin-attached synthetic article of the present invention, woven fabrics made of natural and synthetic fibers, non-woven fabrics such as needle punched fabrics, napped woven fabrics, and knitted fabrics. Cloth, flocked cloth, etc. can be used. Especially for automotive interior applications, PVC (polyvinyl chloride) and TPO
(Thermoplastic olefin), thermoplastic polyester, elastomer, etc., thermoplastic resin sheet, and this sheet laminated with a base fabric or resin foam such as polypropylene, polyethylene, polyvinyl chloride, polyurethane, or for the above-mentioned various decorations The outer skin is used alone, or a backing material is adhered to it, or a resin foam such as polypropylene, polyethylene, polyvinyl chloride or polyurethane is laminated. Also,
There are cases where various hot melts are further attached to these skins for use, but in the present invention, the use is not compulsory because the adhesive has sufficient adhesive strength even without hot melt. When using the skin with hot melt, for example, from among various hot melts such as polyamide-based, modified polyolefin-based, urethane-based, and polyolefin-based ones, the two-layer film resin component to be used may have an affinity and an adhesive property. It is desirable to select good ones.

Constitution of Film In the stamping sheet, the light-weight stampable sheet molded product or the light-weight stampable sheet skin-bonded product according to the present invention, the film interposed on the surface of the substrate or between the substrate and the skin. Is composed of film A and film B. Here, the film A is preferably a resin film that forms an effective impregnated adhesive layer on the base material surface side and remains as a non-venting layer between the base material surface or the base material and the epidermis. It is composed of a resin having the same or similar structure as the thermoplastic resin constituting the base material and having a melting point or a melt viscosity of the same degree or higher than that of the thermoplastic resin. Specifically, such as increasing the degree of polymerization to increase the molecular weight, or partially modifying by copolymerization or grafting, increasing the viscosity by blending another resin, or filling various fillers, etc. There is a way. That is, the same or similar structure means a copolymer to a homopolymer, a blended product, a grafted product, or the like. In particular, when polypropylene is used as the thermoplastic resin constituting the substrate and polypropylene is used as the film resin, the resin constituting the film A has a large molecular weight or LDP.
By blending E (low density polyethylene) or by filling with inorganic fillers such as calcium carbonate, titanium oxide, mica, carbon black, magnesium silicate, etc., the melt viscosity is made higher than the thermoplastic resin constituting the base material. Is desirable. The film B is a resin layer that penetrates into the epidermis to improve the adhesion between the epidermis and the substrate, has the same or similar structure as the thermoplastic resin constituting the substrate, and It is made of a resin whose melting point is lower than that of the resin. Specifically, there are methods of lowering the molecular weight by lowering the degree of polymerization, partial modification by copolymerization or grafting, or lowering the viscosity by blending with another resin. In particular, when polypropylene is used as the thermoplastic resin constituting the substrate and polypropylene is used as the film resin, a polypropylene film having a high melt viscosity is used as the film A and a melting point of 150 ° C. or less is used as the film B. A combination using a low melting point polypropylene film or polyethylene film is desirable. The above-mentioned two-layer film can be manufactured according to a conventionally known method. For example, the film can be multilayered by a dry lamination method or a coextrusion method.
Further, it is possible to provide a thin adhesive layer between the layers of the two-layer film to further improve the adhesiveness.

Next, a method for producing the lightweight stampable sheet molded product and the lightweight stampable sheet skin-bonded product according to the present invention will be described. (1) First, the reinforcing fibers and the thermoplastic resin particles are dispersed in an aqueous surfactant solution in which air microbubbles are dispersed. Next, the obtained dispersion liquid is dehydrated through a porous support to deposit solids in the dispersion liquid, and the deposit is dried to obtain a uniform web. This web is composed of reinforcing fibers and a thermoplastic resin, and particles of the thermoplastic resin are uniformly dispersed in the reinforcing fibers, and the thickness thereof is 1 to 10 mm.

(2) Next, a two-layer film consisting of the film A and the film B is laminated on one side or both sides of the web, and the laminate is heated at a temperature not lower than the melting point of the thermoplastic resin and lower than the decomposition point, The resin is melted and pressure is applied between the cooling plates to solidify it into a sheet to obtain a dense sheet-forming stampable sheet. When the thermoplastic resin is polypropylene, the heating temperature is 170 to 230 ° C, preferably 1
90 to 210 ℃. The reason is that if the temperature exceeds 230 ° C, the polypropylene is decomposed to cause coloration and decrease in strength. The above pressure between the cooling plates is 3 to 50 Kgf / cm ^{2 in} order to obtain a dense stamping sheet made by the papermaking method.
It is desirable to set it within the range. The reason for this is 50 Kgf / cm
^This is because if the pressure exceeds ² , breakage of the reinforcing fiber is likely to occur. It should be noted that the stamping sheet made by the papermaking method may contain additives such as an antioxidant, a light resistance stabilizer, a metal deactivator, a flame retardant, carbon black and magnesium silicate, a colorant and the like. These additives and colorants are, for example, prepared by a method of pre-blending or coating a granular thermoplastic resin, or a method of adding a spray or the like during a papermaking method stun bubble sheet manufacturing process. It can be contained in a bubble sheet.

(3) The sheet-forming stampable sheet (laminated sheet) obtained as described above is reheated to a temperature not lower than the melting point of the constituent resin, and in the case of a skin-bonded product, an expanded sheet After stacking the skin on top, place it in the molding die, adjust the height of the die spacer and the clamping height of the press, etc., and integrate by press molding, and have a predetermined thickness and density Light weight Obtain a stamped sheet molded product or a light-weight stampable sheet skin-bonded product. Here, the heating temperature at the time of such expansion molding can be appropriately selected within a temperature range not lower than the melting point and lower than the decomposition point of the thermoplastic resin constituting the papermaking method stampable sheet. For example, when the thermoplastic resin is polypropylene, the heating temperature is 170 to 230 ° C, preferably 190 to 210 ° C. The method for heating the stampable sheet in the papermaking method includes hot plate heating, far infrared heating, and ventilation heating, and is not particularly limited. The mold temperature may be equal to or lower than the freezing point of the thermoplastic resin, and is usually in the range of room temperature to 60 ° C from the viewpoint of handleability and productivity. Further, the molding pressure varies depending on the shape of the product, but an excessive pressure breaks the reinforcing fibers, so the pressure is usually in the range of 1 to 50 kg / cm ² .

The density of the light-weight stampable sheet molded product thus obtained is controlled by the clearance of the mold and may be smaller than the theoretical density (ρ), preferably 0.8 g / cm ³ or less, more preferably It should be 0.7g / cm ³ or less.
Here, the theoretical density (ρ) is the density when the porosity is zero, and is calculated from the following equation. ρ = 100 / (W _m / ρ _m + W _r / ρ _r ) W _m ; Weight fraction of thermoplastic resin W _r ; Weight fraction of reinforcing fiber ρ _m ; Density of thermoplastic resin ρ _r ; Density of reinforcing fiber The expansion ratio of the lightweight stampable sheet molded product is 1.
It is 1 to 15 times, preferably 1.5 to 10 times. The reason for this is
This is because if the expansion ratio is too large, the difference in temperature between the surface and the interior during heating becomes large when the basis weight is large, and uniform heating is difficult and uneven thickness occurs. On the other hand, if the expansion ratio is too small, the effect of reducing the weight in the required thickness is small. Here, the expansion ratio is a value obtained by dividing the thickness of the expansive material (lightweight stampable sheet molded product) by the theoretical thickness (thickness when the porosity is zero).

[0023]

EXAMPLES The present invention will be specifically described below based on examples. The thermoplastic resin, the reinforced fiber, the two-layer film, and the skin which compose the stampable sheet used in the examples are as follows. -Thermoplastic resin: Homostructured polypropylene (MFR20, melting point 155 ° C, average particle size 500 μm) -Reinforcing fiber: Glass fiber chopped strand A (length 13 mm, diameter 17 μm, 0.005 wt% aminosilane coupling agent treatment, polyethylene oxide type) Converging agent 0.
05 wt% treatment, 5000 converging fibers / bundle) Glass fiber chopped strand B (length 13 mm, diameter 23 μm, aminosilane coupling agent 0.005 wt% treatment, polyethylene oxide converging agent 0.
05wt% treatment, number of bundles 5000 / bundle) ・ Double-layer film; Film X → a double-layer film produced by the co-extrusion method, in which film A (first layer) is a 10% blend of LDPE (low density polyethylene) and a thickness of 20 μm. Polypropylene (MFR 0.6, melting point
145 ° C) and film B (second layer) has a thickness of 25
It is composed of μm polypropylene (MFR12, melting point 130 ° C). Film Y → A two-layer film produced by the dry lamination method, in which film A (first layer) is composed of polypropylene (MFR1.0, melting point 160 ° C.) with a thickness of 30 μm filled with 5% of titanium oxide, and film B (second layer). The layer) is composed of 25 μm thick polypropylene (MFR12, melting point 130 ° C.). Film Z → A two-layer film produced by coextrusion method, in which film A (first layer) is a blend of 10% LDPE (low density polyethylene) and has a thickness of 20 μm polypropylene (MFR 0.6, melting point).
145 ° C) and film B (second layer) has a thickness of 25
It is composed of μm branched polyethylene (MFR15, melting point 115 ° C). -Surface: Polyester nonwoven fabric (thickness 2 mm) has a backing material and no hot melt layer.

Example 1 20.625 g polypropylene particles, 9.375 g glass fiber chopped strand A and
0.8wt% of 7.500g glass fiber chopped strand B
10 l of an aqueous solution of sodium dodecylbenzene sulfonate was stirred and foamed to prepare a dispersion liquid. Then, this dispersion is poured into a paper machine with a paper making area of 250 × 250 mm ² , sucked and defoamed, air-dried, and a web (base material) having a basis weight of 600 g / m ²
I got Next, the obtained web is preheated at 200 ° C., the preheated web and the film X are laminated and laminated, and this laminated body is placed between the cooling plates at 25 ° C. and pressed at a pressure of 5 kgf / cm ^2. Then, a solidified and dense stamping sheet made by the papermaking method was obtained (see FIG. 1). Then, the above-mentioned papermaking stampable sheet is heated with a far infrared heater at a heater setting temperature of 250 ° C. for 2 minutes, and then a skin is placed on the heat-expanded sheet, and a mold with a clearance set to 3.5 mm is used together with the skin. The sheet was compressed / cooled to obtain a light-weight stampable sheet-covered product (see FIG. 2). At this time, the base material expansion ratio (ratio of the actual base material thickness to the theoretical thickness when the porosity is zero) of the skin-bonded product was 4 times. With respect to the light-weight stampable sheet skin-bonded product thus obtained, the air permeability was evaluated by the air permeability test according to ASTM-D737. Table 1 shows the results.

Example 2 20.625 g of polypropylene particles, 9.375 g of glass fiber chopped strand A and
0.8wt% of 7.500g glass fiber chopped strand B
10 l of an aqueous solution of sodium dodecylbenzene sulfonate was stirred and foamed to prepare a dispersion liquid. Then, this dispersion is poured into a paper machine with a paper making area of 250 × 250 mm ² , sucked and defoamed, air-dried, and a web (base material) having a basis weight of 600 g / m ²
I got Next, the obtained web is preheated at 200 ° C., the preheated web and the film X are laminated and laminated, and this laminated body is placed between the cooling plates at 25 ° C. and pressed at a pressure of 5 kgf / cm ^2. Then, a solidified dense stamping sheet made by the papermaking method was obtained. Then, the above-mentioned papermaking stampable sheet is heated with a far infrared heater at a heater setting temperature of 250 ° C. for 2 minutes, and then a skin is placed on the heat-expanded sheet, and a mold with a clearance set to 3.5 mm is used together with the skin. The base material was compressed / cooled to obtain a light-weight stampable sheet-covered product. At this time, the expansion ratio of the base material of the skin-bonded product was 4 times. From the light-weight stampable sheet skin-bonded product thus obtained, a peel test piece (T: 150 mm long, 25 mm wide)
The peel strength was measured as an average value of the maximum load and the minimum load by a normal tensile test (pulling speed 50 mm / min) in a state in which a peel test piece) was cut out and opened 50 mm from the end. Further, the air permeability was evaluated by the air permeability test according to ASTM-D737. The results are also shown in Table 1.

Example 3 A film Y was used in place of the film X used in Example 2, except that
A light-weight stampable sheet skin-bonded product was obtained in the same manner as in Example 2, and the peel strength and air permeability of this skin-bonded product were measured. The results are shown in Table 1.

Example 4 A film Z was used in place of the film X used in Example 2, except that
A light-weight stampable sheet skin-bonded product was obtained in the same manner as in Example 2, and the peel strength and air permeability of this skin-bonded product were measured. The results are shown in Table 1.

(Comparative Examples 1, 2 and 3) The same procedure as in Example 2 was repeated except that the resin layers constituting the film X were used as individual film layers instead of the film X used in Example 2. Thus, light-weight stampable sheet skin-bonded products were obtained, and the peel strength and air permeability of these skin-bonded products were measured (Comparative Examples 1 and 2). Further, instead of using the film X used in Example 2, a polypropylene (MFR1.0) resin layer, which constitutes the film Y of Example 2 and was filled with 5% of titanium oxide, was used as a single film layer. A light-weight stampable sheet skin-bonded product was obtained in the same manner as in Example 2, and the peel strength and air permeability of this skin-bonded product were measured (Comparative Example 3). The results are also shown in Table 1.

Further, a test piece having a length of 150 mm and a width of 50 mm was prepared from the light-weight stampable sheet skin-bonded product thus obtained, and the span was 100 mm and the crosshead speed was 50 mm.
A bending test in which a load was applied from the skin side was carried out at 50 mm / min, and the maximum load was measured. The results are also shown in Table 1.

[0030]

[Table 1]

As is clear from the results shown in Table 1,
The light-weight stampable sheet-covered article according to the present invention has a polypropylene film made of a resin having a melting point or a melt viscosity equal to or higher than that of polypropylene constituting the substrate, between the substrate and the skin. Therefore, the non-breathability can be improved. Further, at the skin-side interface, the polypropylene film having a lower melting point than the polypropylene constituting the base material forms the impregnated adhesive layer on the skin side at the time of sticking the skin, so that the anchoring effect improves the adhesion strength. On the other hand, at the interface on the base material side, a polypropylene film made of a resin having a melting point or melt viscosity that is at least the same as that of the polypropylene forming the base material forms an impregnated adhesive layer of sufficient thickness on the base material surface side. The adhesion effect is improved by the anchor effect. Therefore, according to the present invention, the peel strength is improved as compared with the prior art in which a single-layer polypropylene film is interposed. further,
The mechanical strength of the surface layer was improved by the impregnation curing, and the sandwich structure (sandwich effect) of the surface layer and the inner layer improved the rigidity and load resistance.

[0032]

As described above, according to the present invention,
It is possible to provide a paper-made stampable sheet that has excellent adhesiveness and non-breathability, which makes it possible to provide lightweight stampable sheet moldings with improved non-breathability, and excellent adhesion and non-breathability between the base material and the epidermis. It is possible to easily obtain the above-described porous light-weight stampable sheet skin-bonded product. In particular, the light-weight stampable sheet-covered product according to the present invention can be advantageously applied to automobile interior materials, such as ceiling materials and door trim materials, which are desired to be lightweight.

[Brief description of drawings]

FIG. 1 is a view showing a cross-sectional structure of a papermaking method stampable sheet according to the present invention.

FIG. 2 is a view showing a cross-sectional structure of a light-weight stampable sheet skin-bonded product according to the present invention.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location B32B 31/20 7148-4F B32B 31/20 (72) Inventor Taiji Matsumoto Chuo-ku, Chiba City, Chiba Prefecture Kawasaki-cho No. 1 Kawasaki Steel Co., Ltd., Technical Research Laboratory (72) Inventor Masami Fujimaki, Kawasaki-cho, Chuo-ku, Chiba City, Chiba Prefecture Kawasaki Steel Co., Ltd., Technical Research Center (72) Inventor Tomoe Shige, Chiba, Chiba Central 1st Kawasaki-cho, Kawasaki Steel Co., Ltd., Technical Research Laboratory (72) Inventor Shigeru Takano 1st Kawasaki-cho, Chuo-ku, Chiba City, Chiba Prefecture Technical Research Laboratory, Kawasaki Steel Co., Ltd. (72) Shinpei Masui Shinkawa, Chuo-ku, Tokyo 2-27-1 (Tokyo Sumitomo Twin Building East Building) Sumitomo Chemical Co., Ltd. (72) Inventor Satoshi Funakoshi 2-1, Tsukahara, Takatsuki City, Osaka Prefecture No. 0-1 Sumitomo Kagaku Kogyo Co., Ltd. (72) Inventor Hiroyuki Yoshitake, 1 Kawasaki-cho, Chuo-ku, Chiba, Chiba Prefecture Within Cape Lasheet Co., Ltd. (72) Ina Masaaki Sunada 1 Kawasaki-cho, Chuo-ku, Chiba Address within Cape La Sheet Co., Ltd.

Claims (6)

[Claims] 1. A papermaking method stampable sheet obtained by heat-pressing and solidifying a sheet-shaped web obtained by forming a mixture of a thermoplastic resin and a reinforcing fiber into a paper, which is the same as the thermoplastic resin constituting the web. Alternatively, a film A made of a resin having a similar structure and having a melting point or a melt viscosity similar to or higher than that of the thermoplastic resin, and a structure identical or similar to the thermoplastic resin forming the web are provided. A dense papermaking process in which a film made of a resin having a melting point lower than that of the thermoplastic resin and having a film B is laminated so that the film A is located on the web side and integrated by thermocompression bonding. Law stampable sheet. 2. The thermoplastic resin forming the web is polypropylene having a melting point of 135 ° C. or higher, and the resin forming the film A has the same or similar structure as the thermoplastic resin and has a melting point. Is polypropylene having a temperature of 135 ° C. or higher, and as the resin constituting the film B, polypropylene or polyethylene having the same or similar structure as the thermoplastic resin and having a lower melting point than the thermoplastic resin is used. The stampable sheet according to claim 1, wherein the stampable sheet is a papermaking method. 3. The stamping sheet according to claim 1, wherein the film A is filled with a filler. 4. A polypropylene is used as a thermoplastic resin constituting the web, and the resin constituting the film A has the same or similar structure as the thermoplastic resin and is filled with a filler to obtain the heat. Using polypropylene having a melt viscosity equal to or higher than that of the thermoplastic resin, the resin constituting the film B has the same or similar structure as the thermoplastic resin,
The polypropylene stamping sheet according to claim 1, wherein polypropylene having a melting point lower than that of the thermoplastic resin is used. 5. A sheet-forming stampable sheet according to any one of claims 1 to 4 is heated and expanded to obtain an expanded sheet, and the expanded sheet has a theoretical density (when the porosity is zero) after molding. A light-weight stampable sheet molded article characterized by being made into a porous body by compression molding so as to have a density lower than that of (1). 6. A sheet-forming stampable sheet according to any one of claims 1 to 4 is expanded by heating to form an expanded sheet, and the expanded sheet and the skin are superposed, and the density after molding is the theoretical density ( A light-weight stampable sheet skin-bonded product characterized in that it is made into a skin-bonded porous body by compression molding so that it becomes smaller than the density when the porosity is zero).