JP2003175573A - Stampable sheet with excellent adhesive property and non-gas-permeability manufactured by paper making process - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To manufacture a stampable sheet with excellent adhesive properties and non-gas-permeability which is to be a raw material for a porous product exhibiting excellent adhesiveness and complete non-gas-permeability. <P>SOLUTION: The stampable sheet is prepared by heat-pressing and solidifying a sheet-like web prepared by molding a mixture of a polypropylene with a melting point of at least 135°C and a reinforcing fiber by a paper making process; and a film consisting of a film A constituted of a resin with the same or similar structure as the polypropylene constituting the web and a melting point or a melt viscosity of the same level or higher as the polypropylene, and a film B constituted of a resin with a melting point of at least 10°C higher than that of the polypropylene constituting the web, and if necessary, a film consisting of a film C constituted of a resin with a melting point of the same or lower than the melting point of the polypropylene. The film A is positioned on the web side, and the film A, the film B and the film C are laminated in this order to integrate the laminated film by heat pressing. <P>COPYRIGHT: (C)2003,JPO

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 having excellent adhesiveness and non-breathability, and a lightweight stampable sheet molded product and a lightweight stampable sheet skin-bonded product produced from this sheet. In particular, the light-weight stampable sheet skin-bonded 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 product and a method for manufacturing the same have been proposed, for example, in Patent Documents 1 and 2. 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 (for example, see Patent Document 3). A technique for improving the adhesion between the base material and the epidermis and preventing the resin from seeping out to the epidermis surface by pressure molding with a thermoplastic resin containing an inorganic filler interposed between the epidermis and the epidermis (for example, , Patent Document 4), a technique for improving the adhesiveness between the base material and the outer skin and improving the outer appearance on the outer skin side by press-molding the outer skin laminated with the thermoplastic resin porous sheet and the expansion sheet ( For example, refer to Patent Document 5).

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 Of the light-weight stampable sheet, forming a so-called effective adhesive impregnated layer, which 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]

[Patent Document 1] Japanese Patent Laid-Open No. 60-179234

[Patent Document 2] JP-A-62-161529

[Patent Document 3] JP-A-5-16274

[Patent Document 4] JP-A-4-331137

[Patent Document 5] JP-A-5-16277

[0008]

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. (EN) Provided are a light-weight stampable sheet molded product exhibiting excellent properties, and a light-weight stampable sheet skin-bonded product having excellent adhesion between a base material and a skin and having complete non-air permeability.

[0009]

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 papermaking method stampable sheet obtained by heat-pressing and solidifying a sheet-like web obtained by paper-forming a mixture of polypropylene having a melting point of 135 ° C. or more and reinforcing fibers. A film having a structure which is the same as or similar to that of the polypropylene forming the web, and made of a resin having a melting point or a melt viscosity similar to or higher than that of the polypropylene, and the polypropylene forming the web. A dense sheet-forming stampable sheet obtained by laminating a film composed of a film B made of a resin having a melting point of 10 ° C. or higher so that the film A is located on the web side, and integrating the films by thermocompression bonding. (2) In a papermaking method stampable sheet obtained by heat-pressing and solidifying a sheet-like web obtained by paper-forming a mixture of polypropylene having a melting point of 135 ° C. or more and reinforcing fiber, the same as the polypropylene constituting the web. Alternatively, a film A made of a resin having a similar structure and having a melting point or melt viscosity equal to or higher than that of the polypropylene, and a resin having a melting point of 10 ° C. or more higher than that of the polypropylene forming the web. A film made of a film B made of a resin having a melting point of the polypropylene which is the same as or lower than that of the polypropylene constituting the web.
Film A-Film B-
A dense paper stampable sheet obtained by laminating films C in this order and integrating them by thermocompression bonding. (3) In the invention described in (1) or (2) above, a dense sheet-forming stampable sheet characterized in that a polyamide resin is used as a resin forming the film B.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The feature of the paper-making stampable sheet according to the present invention is that the film A exhibits adhesiveness to a substrate.
And a two-layer film consisting of a non-breathable film B,
Alternatively, a three-layer film consisting of a film A showing adhesiveness with a substrate, a film B showing non-air permeability and a film C showing adhesion with a surface layer is laminated on a paper sheet made of a thermoplastic resin and reinforcing fibers. There is a point. As a result, the stampable sheet made by the above papermaking method is heated and pressed (expansion molding).
Then, it is possible to obtain a porous stampable sheet molded article having excellent adhesion between the base material and the skin and exhibiting complete non-air permeability. 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-covered product which is excellent and completely non-breathable. Here, in the above 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 the same as or higher than that of the thermoplastic resin forming the substrate, the surface of the substrate An impregnated adhesive layer having a sufficient thickness is formed on the side and acts as an adhesive layer for improving the adhesion strength between the base material and the non-venting layer by the anchor effect. Since the film B is made of a resin having a melting point sufficiently higher than that of the thermoplastic resin forming the base material, the film B acts as a non-venting layer. In addition, this film B, when using a skin having an adhesive layer such as a hot melt layer,
Since a smooth surface that facilitates fixation of the hot melt layer is formed during laminating the skin, it also functions as an adhesion auxiliary layer. The film C is advantageous when a skin without an adhesive layer is used, and since it is composed of a resin having a melting point which is the same as or lower than that of the thermoplastic resin which constitutes the substrate, the film C melts during the laminating of the skin. Acts as an adhesive layer with the epidermis. As described above, according to the present invention, regardless of whether or not the epidermis has adhesiveness, the base material and the epidermis have excellent adhesion, and a porous light-weight stampable sheet epidermis-bonding that ensures complete non-breathability. Goods can be provided stably.

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 melt viscosity equal to or higher than that of the thermoplastic resin, and a thermoplastic resin constituting the web. A dense sheet-forming stampable sheet obtained by laminating a film composed of a film B made of a resin having a sufficiently high melting point so that the film A is located on the web side, and integrating the films by thermocompression bonding, or It has the same or similar structure as the thermoplastic resin constituting the web, and has a melting point or melt viscosity similar to that of the thermoplastic resin. Or more, a film A made of a resin, a film B made of a resin having a melting point sufficiently higher than that of the thermoplastic resin forming the web, and a melting point of the thermoplastic resin forming the web. A film made of a film C composed of a resin having the same degree or less is laminated in the order of film A-film B-film C so that the film A is located on the web side, and integrated by thermocompression bonding. It is a precise stampable sheet. In addition,
The above-mentioned papermaking method stampable sheet of the present invention is expanded by heating to form an expanded sheet, and the expanded sheet is compression-molded so that the density after molding is smaller than the theoretical density (density when the porosity is zero). Thus, a light-weight stampable sheet molded product can be manufactured by using a porous body. Furthermore, the above-mentioned papermaking method stampable sheet of the present invention is expanded by heating to form an expanded sheet, and the expanded sheet and the skin are superposed, and the density after molding is higher than the theoretical density (density when the porosity is zero). A light-weight stampable sheet-covered article can also be manufactured by making a skin-bonded porous body by compression molding so as to be small.

Reinforcing Fibers In the present invention, the reinforcing fibers constituting the substrate are inorganic fibers such as glass fibers, carbon fibers, boron fibers and other metal fibers, or aramid fibers, polyester fibers, polyamide fibers, wood fibers, etc. Organic fibers of can be used. In particular, it is more preferable to use glass fiber in terms of cost and property balance.

The fiber length of this reinforcing fiber is excellent in the reinforcing effect and secures the formability at the time of 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. It is desirable that the fiber diameter of the reinforcing fiber is in the range of 5 to 30 μm, preferably 10 to 25 μm from the viewpoint of ensuring the reinforcing effect and the expanding 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 μm.
This is because if it exceeds m, 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 matrix resin, a treatment with a silane coupling agent is performed. As the silane coupling agent, it is preferable to use a vinylsilane-based, aminosilane-based, epoxysilane-based, methacrylsilane-based, chlorosilane-based, or mercaptosilane-based coupling agent. The surface treatment of the reinforcing fiber with such a silane coupling agent is carried out by a known method such as a method of spraying the silane coupling agent solution while stirring the reinforcing fiber or a method of immersing the reinforcing fiber in the coupling agent solution. It can be carried out. The treatment amount of the silane coupling agent was 0.
It is desirable to set it in the range of 001 to 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 light-weight stampable sheet molded product, it is desirable that the reinforcing fiber be opened into a single fiber. 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% with respect to the reinforcing fiber.
%, Preferably 0.05 to 0.2 wt% is desirable. 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%.

Regarding the thermoplastic resin, examples of the thermoplastic resin constituting the base material in the present invention include polyolefins such as polyethylene and polypropylene, resins such as polystyrene, polyvinyl chloride, polyethylene terephthalate, polycarbonate, polyamide, polyacetal, and the like. Copolymers containing the above resin as a main component (for example, ethylene-vinyl chloride copolymer, ethylene-vinyl acetate copolymer, styrene-butacien-acrylonitrile copolymer, etc.), graft compounds, or blended products of these resins, etc. Can be used. Of these, polypropylene is preferred. The weight average molecular weight (hereinafter, simply referred to as “M _W ”) of this thermoplastic resin is preferably in the range of 50,000 to 700,000. The reason for this is that if M _W is less than 50,000,
This is because the melt viscosity is low, and the wettability and adhesiveness to the reinforcing fiber are improved, but the resin is apt to become brittle, and the mechanical properties of the fiber-reinforced thermoplastic resin base material formed by paper forming are deteriorated.
On the other hand, 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 reinforcing fiber joint 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, the resin particle size is preferably 50 to 2000 μm.
It is desirable to use those within the range. The reason for this is that if the resin particle size is less than 50 μm, troubles 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 is uniformly dispersed in the reinforcing fiber. 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 adhesiveness 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, the 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 has an amount of the modifying group of 0.02 to 3.0 wt% (100
X weight of modifying group / weight of thermoplastic resin), preferably 0.
It is desirable to be within the range of 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, if it exceeds 3.0 wt%, disadvantages such as embrittlement of the thermoplastic resin and coloring of the sheet may be caused. When the above modified resin is used in combination as the thermoplastic resin,
A fiber-reinforced thermoplastic resin substrate may be produced by laminating webs made of respective resins, or these resins may be melt-kneaded and pulverized in advance with an extruder or the like, or one resin may be It is also possible to produce a fiber-reinforced thermoplastic resin substrate by subjecting a resin-coated product to paper-forming molding.

Mixing Ratio of Reinforcing Fibers and Thermoplastic Resin In the fiber-reinforced thermoplastic resin substrate constituting the lightweight stampable sheet molded article produced from the stamping sheet of the papermaking method of the present invention, the reinforcing fiber and the thermoplastic resin are combined. The mixing ratio is preferably 20/80 to 70/30 in terms of weight ratio (fiber / resin). 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.

About the skin As a decorative skin constituting the light-weight stampable sheet skin-attached synthetic product manufactured from the stamping sheet of the papermaking method of the present invention, the decorative skin is a woven fabric made of natural or synthetic fibers,
A non-woven fabric obtained by needle punching, a raised woven fabric, a knitted fabric, a flocked fabric, or the like can be used. In particular, for automobile interior applications, thermoplastic resin sheets such as PVC (polyvinyl chloride), TPO (thermoplastic olefin), thermoplastic polyester, and elastomer, and base sheet, polypropylene, polyethylene, polyvinyl chloride, polyurethane on this sheet. Laminated with resin foam such as the above, or the above-mentioned various decorative skins alone, and a backing material attached thereto, or polypropylene or polyethylene,
A laminate of resin foams such as polyvinyl chloride and polyurethane is used. In addition, although various hot melts may be further attached to these skins,
In the present invention, since it has sufficient adhesive strength without hot melt, its use is not compulsory. 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.

Regarding the constitution of the film In the light-weight stampable sheet skin-bonded product produced from the stamping sheet of the papermaking method of the present invention, the film interposed between the base material and the skin is Film A-Film B, or It is composed of film A-film B-film C. Here, the film A is a resin layer that penetrates into the base material side to form an impregnated adhesive layer having a sufficient thickness on the base material surface side, and by the anchor effect thereof, improves adhesion with the base material. The resin having the same or similar structure as the thermoplastic resin constituting the base material and having the melting point or the melt viscosity equal to or higher than that of the thermoplastic resin. Specifically, there are methods such as increasing the degree of polymerization to increase the molecular weight, or partially modifying by copolymerization or grafting, or increasing the viscosity by blending another resin. 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 forming the base material, it is preferable to use a polyolefin resin because of its adhesiveness to the base material. When polypropylene is used as the thermoplastic resin constituting the base material and polypropylene is used as the resin constituting film A, the resin of film A has a large molecular weight or LDPE.
(Low density polyethylene) may be blended. The film B is a film that acts as a non-venting layer,
It is desirable that the resin film that does not melt at the temperature at which the thermoplastic resin that constitutes the base material melts and that gives a degree of expansion that does not hinder the shapeability of the sheet during expansion molding is used. It is made of a resin having a melting point sufficiently higher than that of the plastic resin. For example, polyolefin, polystyrene, polyvinyl chloride, polyethylene terephthalate, polycarbonate, polyamide, polyacetal, and copolymers containing these resins as main components (for example, ethylene-vinyl chloride copolymer, ethylene-vinyl acetate copolymer, etc.) ), A graft compound, or a blended product of these resins can be used. In particular, when polypropylene is used as the thermoplastic resin constituting the base material, it does not melt within the range of sheet solidification and pressure molding temperature of 190 to 210 ° C (a resin having a melting point higher than polypropylene by 10 ° C or more). ), Or a resin exhibiting a high melt viscosity, such as a polyamide resin, is preferably used. The film C is a film layer that is advantageous when a non-adhesive skin is used, and acts as an adhesive layer with the skin, and is made of a resin having a lower melting point than the thermoplastic resin that constitutes the base material. There is no other limitation. For example, polyolefin, polystyrene, polyvinyl chloride, polyethylene terephthalate, polycarbonate, polyamide, polyacetal, and the like, as well as copolymers and graft compounds containing these resins as main components, or blends of these resins can be used. The above-mentioned two-layer or three-layer multilayer film can be manufactured by a conventionally known method. For example, the film can be multilayered by a dry lamination method or a coextrusion method. Furthermore, it is possible to provide a thin adhesive layer between the layers of the multilayer film to further improve the adhesiveness.

Next, a method for producing a light-weight stampable sheet molded product and a light-weight stampable sheet skin-bonded product by using the papermaking method stampable sheet 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 multilayer film consisting of film A-film B or film A-film B-film C is laminated on one side or both sides of the above web, and this laminated body is decomposed above the melting point of the thermoplastic resin. The resin is melted by heating at a temperature below the point and solidified into a sheet by applying pressure between cooling plates to obtain a dense sheet-forming stampable sheet. The multilayer film is laminated on both sides of the web when the appearance of both sides of the substrate is required to be improved depending on the intended use of the molded product. Here, when the thermoplastic resin is polypropylene, the heating temperature is 170 ~ 230 ℃, preferably 190
~ 210 ℃. The reason for this is that if the temperature exceeds 230 ° C., coloration or strength reduction due to decomposition of polypropylene is caused. Further, the pressure between the cooling plates is preferably within the range of 3 to 50 kgf / cm ^{2 in} order to obtain a dense stampable sheet for papermaking. The reason for this is that the pressure exceeding 50 kgf / cm ² tends to cause damage to the reinforcing fibers. It should be noted that the stampable sheet for the papermaking method may contain additives such as antioxidants, light stabilizers, metal deactivators, flame retardants, carbon black, and colorants. These additives and colorants, for example, a method of premixing or coating a granular thermoplastic resin, or during the papermaking method stampable sheet manufacturing process,
It can be contained in the stamping sheet for the papermaking method by a method such as addition by spraying.

(3) Then, 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 stampable sheet molded product or a lightweight 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, and 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.
1 to 25 times, preferably 1.5 to 10 times, more preferably 1.5 to
8 times. The reason for this is that if the expansion ratio is too large, the temperature difference 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).

[0025]

EXAMPLES The present invention will be specifically described below based on examples. The thermoplastic resin, the reinforcing fiber, the multilayer film, and the skin which compose the stampable sheet used in the examples are as follows. -Thermoplastic resin; polypropylene particles (weight average molecular weight
200,000, MFR 65, average particle size 500μm) ・ Reinforcing fiber; Glass fiber A (length 25mm, diameter 17μm) Glass fiber B (length 25mm, diameter 23μm) ・ Multilayer film; Film X → 2 layer film by dry lamination method Thus, the film A (first layer) is composed of polypropylene (MFR 9, melting point 155 ° C) having a thickness of 60 μm, and the film B is
The (second layer) is composed of 6-nylon having a thickness of 25 μm (melting point 215 ° C.). Film Y → a three-layer film produced by the dry laminating method. Film A (first layer) is composed of polypropylene (MFR 9, melting point 155 ° C) with a thickness of 40 μm, and film B
The (second layer) is composed of 25-μm-thick 6-nylon (melting point 215 ° C.), and the film C (third layer) is composed of 40-μm-thick polypropylene (MFR 9, melting point 130 ° C.). Film Y ′ → a three-layer film produced by the dry lamination method, in which film A (first layer) is composed of polypropylene (MFR 9, melting point 155 ° C.) having a thickness of 60 μm, and film B
The (second layer) is made of 25-μm-thick 6-nylon (melting point 215 ° C.), and the film C (third layer) is made of 40-μm-thick polyethylene (MFR 15, melting point 115 ° C.). Film Z → Comprised of 40 μm thick polypropylene (MFR 9, melting point 140 ° C.). -Outer skin: Outer skin A-> polyester non-woven fabric (thickness 2 mm) has a backing material and a hot melt layer. Outer skin B → polyester non-woven fabric (thickness 2 mm) has a backing material and no hot melt layer.

Example 1 A composition having a dry weight of 40% polypropylene particles, 35% glass fiber A and 25% glass fiber B, and mixing these raw materials so that the total weight is 600 g / m ^2. Paper was made by using the above method to obtain a web (base material). next,
The web and the film X thus obtained were laminated on each other so as to form a film X / web. 21 this stack
Preheated at 0 ° C., the preheated laminated body was placed between cooling plates at 25 ° C., and pressed at a pressure of 5 kgf / cm ² to obtain a solidified dense stamping sheet for papermaking (see FIG. 1). And
The papermaking method stampable sheet is heated with a far-infrared heater at a set temperature of 250 ° C. for 2 minutes, and then the skin A is placed on the heat-expanded sheet, and the base material is used together with the skin A by a mold having a clearance of 2.5 mm. 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. A test piece with a length of 150 mm and a width of 50 mm was prepared from the light-weight stampable sheet skin-bonded product thus obtained, with a span of 100 mm and a crosshead speed of 50 mm / min.
A three-point bending test in which a load was applied from the skin side was carried out, and the maximum load was measured. In addition, the maximum load and the minimum load are obtained by cutting a peeling test piece (T-peel test piece) with a length of 150 mm and a width of 25 mm and opening it by 50 mm from the end by a normal tensile test (pulling speed 50 mm / min). The peel strength was measured as the average value of Furthermore, the air permeability was evaluated by the air permeability test based on ASTM-D737. The results are shown in Table 1.

(Example 2) A sheet-forming method stampable sheet similar to that in Example 1 was prepared, and the obtained sheet-forming method stampable sheet alone was processed in the same manner as in Example 1 to obtain a clearance of 2.
By using the mold set to 0 mm, a light-weight stampable sheet molded product with no skin attached was obtained (see FIG. 3). At this time, the base material expansion ratio was 4 times. With respect to the light-weight stampable sheet molded product thus obtained, the maximum load, peel strength and air permeability were measured in the same manner as in Example 1. The results are also shown in Table 1.

(Example 3) A lightweight stampable sheet was prepared in the same manner as in Example 1 except that the film Y was used in place of the film X used in Example 1 and the skin B was used in place of the skin A. A skin-bonded product was obtained (see FIG. 4). At this time, the expansion ratio of the base material of the skin-bonded product was 4 times. With respect to the light-weight stampable sheet skin-attached product thus obtained, the maximum load, in the same manner as in Example 1,
The peel strength and air permeability were measured. The results are also shown in Table 1.

(Example 4) A light-weight stampable was carried out in the same manner as in Example 1 except that the film Y'was used instead of the film X used in Example 1 and the skin B was used instead of the skin A. A sheet-epidermis-bonded product was obtained. At this time, the expansion ratio of the base material of the skin-bonded product was 4 times. With respect to the light-weight stampable sheet skin-bonded product thus obtained, the maximum load, peel strength and air permeability were measured in the same manner as in Example 1. The results are also shown in Table 1.

(Comparative Example) A light-weight stampable sheet-covered article was obtained in the same manner as in Example 1 except that the film Z was used instead of the film X used in Example 1 (see FIG. 5). . At this time, the expansion ratio of the base material of the skin-bonded product was 4 times. With respect to the light-weight stampable sheet skin-bonded product thus obtained, the maximum load, peel strength and air permeability were measured in the same manner as in Example 1. The results are also shown in Table 1.

[0031]

[Table 1]

As is clear from the results shown in Table 1,
The light-weight stampable sheet molded article or the light-weight stampable sheet skin-bonded article produced from the papermaking method stampable sheet according to the present invention is a nylon film having a high melting point as compared with polypropylene constituting the substrate, Since it remains between the surface or substrate and the epidermis, it is possible to achieve complete impermeability. In addition, since the nylon film layer having high rigidity and not melting during preheating is present on the surface of the base material or between the base material and the skin, the polypropylene of the base material side adhesive layer vigorously penetrates into the voids inside the base material. As a result, the load resistance was improved as compared with the case where only the polypropylene film was used. In addition, for a skin having a hot-melt layer, the non-melt layer (nylon film layer) forms a smooth surface that easily adheres to the hot-melt layer during laminating the skin, and therefore adheres more than polypropylene film alone. Strength improved. Furthermore, when a resin layer having a melting point lower than that of the thermoplastic resin constituting the base material is provided outside the non-melting layer (nylon film layer), even if a skin having no hot-melt layer is used, Good adhesion was exhibited between the epidermis. Thus, by appropriately selecting the multilayer film to be interposed between the base material and the epidermis, regardless of the presence or absence of the hot melt layer of the epidermis, excellent adhesion between the base material and the epidermis, and complete non-air permeability It is now possible to obtain a secure, light-weight stampable sheet with a laminated skin.

[0033]

As described above, according to the present invention,
It is possible to provide a stamping sheet with a papermaking method that has excellent adhesiveness and non-breathability, which enables the formation of a lightweight stampable sheet molded article that exhibits complete non-breathability, and the adhesion between the base material and the epidermis regardless of the adhesiveness of the epidermis. It is possible to easily obtain a porous light-weight stampable sheet and skin-bonded product which has excellent properties and ensures complete non-breathability. In particular, the light-weight stampable sheet skin-bonded product produced by using the paper-making stampable sheet according to the present invention can be advantageously applied to automobile interior materials for which weight reduction is desired, such as ceiling materials and door trim materials.

[Brief description of drawings]

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

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

FIG. 3 is a view showing a cross-sectional structure of a lightweight stampable sheet molded product according to the present invention.

FIG. 4 is a view showing another cross-sectional structure of the light-weight stampable sheet skin-bonded product according to the present invention.

FIG. 5 is a view showing a cross-sectional structure of a light-weight stampable sheet skin-bonded product according to the prior art.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI Theme Coat (reference) B29L 9:00 B29L 9:00 (72) Inventor Taiji Matsumoto 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Kawasaki Inside Steel Technology Co., Ltd. (72) Inventor Shigeru Takano 1 Kawasaki-cho, Chuo-ku, Chiba, Chiba Prefecture Inside Kawasaki Steel Co., Ltd. (72) Inoue Masui 2-27-1, Shinkawa, Chuo-ku, Tokyo (Tokyo Sumitomo Twin Building East Building) Sumitomo Chemical Co., Ltd. (72) Inventor Satoshi Funakoshi 2-10-1 Tsukahara, Takatsuki City, Osaka Prefecture Sumitomo Kagaku Kogyo Co., Ltd. (72) Inventor Hiroyuki Yoshitake Chiba Chiba Prefecture 1 Kawasaki-cho, Chuo-ku, Tokyo Cape Rasheet Co., Ltd. (72) Inventor, Yoshiaki Sunada 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Cape Lasheet Stock In-house F-term (reference) 4F100 AG00 AK01B AK01C AK01D AK07 AK07A AK46C BA02 BA03 BA04 DE01 DG01 DG01A EH41A EJ17 EJ17A EJ42 EJ42A JA04B JA04D JA06B JA06D JD02 JL11 YY00A YY00B YY00C 4F208 AA11C AA29 AC03 AE10 AG01 AG03 MA01 MA02 MB01 MB22 MC01 MG04 MG11 MH06

Claims (3)

[Claims] 1. A paper-forming stampable sheet obtained by heat-pressing and solidifying a sheet-shaped web obtained by forming a mixture of polypropylene having a melting point of 135 ° C. or higher and reinforcing fibers into a polypropylene, which constitutes the web. A film A made of a resin having the same or similar structure to that of the polypropylene and having a melting point or a melt viscosity similar to or higher than that of the polypropylene, and a resin having a melting point higher than that of the polypropylene constituting the web by 10 ° C. or more. A dense stampable sheet made by a paper-making method, which is obtained by stacking a film composed of the film B and the film B so that the film A is located on the web side and integrating them by thermocompression bonding. 2. A sheet-forming web obtained by forming a mixture of polypropylene having a melting point of 135.degree. A film A made of a resin having the same or similar structure to that of the polypropylene and having a melting point or a melt viscosity similar to or higher than that of the polypropylene, and a resin having a melting point higher than that of the polypropylene constituting the web by 10 ° C. or more. And a film C composed of a resin having a melting point equal to or lower than the melting point of the polypropylene forming the web, the film A being formed so that the film A is located on the web side. Dense paper obtained by laminating film B and film C in this order and integrating them by thermocompression bonding. Law stampable sheet. 3. The stamping sheet according to claim 1 or 2, wherein a polyamide resin is used as the resin forming the film B.