KR100278231B1 - Stamping molding material with excellent mechanical properties and its manufacturing method - Google Patents

Abstract

1. TECHNICAL FIELD OF THE INVENTION

Glass fiber reinforced thermoplastic resin composite (stamping molding material) with stamping molding, high strength, high modulus, excellent fluidity and no color staining.

2. The technical problem to be solved by the invention

It improves the wettability and adhesion of the conventional stamping molding material by the papermaking method, expresses the adhesive action of the functional groups (additives that contribute to the adhesion of the interface) to the silane coupling agent in particular, and has no problems such as color staining. Excellent fluidity and mechanical properties.

3. Summary of Solution to Invention

A stamping molding formed by dispersing a glass fiber and granular thermoplastic resin dispersed in a surfactant-containing aqueous medium in which air bubbles are dispersed, floating on a porous support to obtain a sheet-like web, applying heat and pressure to the web, and solidifying the sheet. Materials and manufacturing methods thereof.

4. Important uses of the invention

Automotive parts such as bumper beams.

Description

Stamping molding material with excellent mechanical properties and its manufacturing method

1 is a graph showing the relationship between the average number of functional groups in the matrix resin and the bending strength.

2 is a graph showing the relationship between the average number of functional groups in the matrix resin and the bending strength.

3 is a graph showing the relationship between the weight ratio and the flexural strength of glass fibers in stamping molding materials.

The present invention relates to a glass fiber reinforced thermoplastic resin composite material (stamping molding material) capable of stamping molding, having high strength, high modulus of elasticity, excellent fluidity, and no color staining, and a method of manufacturing the same.

As a means of adding high strength and high stiffness features while taking advantage of the molding advantages of conventional thermoplastic resins, a compounding technology by adding high modulus fibers such as glass fibers is known. This glass fiber reinforced thermoplastic resin composite material is used as a material for various structural members requiring light weight, high rigidity and high strength.

Among them, a plate- or sheet-type composite material having a relatively long glass fiber is attracting attention as a material for a large structural member.

This material is usually heat-treated below the melting point or softening point of the matrix resin and then molded to give a mold.

A web-making process is known as a method for producing a plate- or sheet-shaped material suitable for molding (stamping molding) of a large member using a press.

The papermaking method disperses glass filaments and granular thermoplastic resins in a solution containing a micro-bubble, and supplies the dispersion onto a porous support similar to the papermaking process to form sheet-like webs, and heat and pressure are applied to the webs. It is a method for producing a compacted sheet-shaped glass fiber reinforced thermoplastic resin composite material.

This technique is disclosed in Japanese Patent Application Laid-Open No. 2-48423 or Japanese Patent Application Laid-Open No. 60-158227.

The present invention is directed to a glass fiber reinforced thermoplastic resin composite material (hereinafter, referred to as a stamping molding material) obtained by using the papermaking method, and the mechanical properties such as excellent strength and elastic modulus of the stamping molding material are low strength and low elastic modulus matrix. The load applied to the phosphorus resin is sufficiently shared and exerted on the glass fiber having high strength and high elastic modulus.

The sharing of the load on the glass fibers proceeds through the interface between the fibers and the resin, ie the outer surface of the fibers.

For this reason, the mechanical properties of the stamping molding material and the structural member obtained by molding the same improve as the wettability and adhesion between the fibers and the resin are sufficient.

However, the mechanical properties of the conventional stamping molding material obtained by the papermaking method were not necessarily sufficient.

As a method of improving the wettability and adhesiveness of an interface, the method of adding a silane coupling agent to a web is known as disclosed in Unexamined-Japanese-Patent No. 63-41128.

Such addition of only the silane coupling agent is insufficient in wettability and adhesion between the glass fiber and the matrix resin.

In addition, as a method for improving the mechanical properties, in order to improve the wettability of the interface, when the melt viscosity of the thermoplastic resin is reduced, that is, the molecular weight is reduced, the wettability is improved, but the matrix resin is weakened, resulting in a decrease in the mechanical properties.

The method of improving the adhesiveness of the interface of glass fiber and resin is also examined in the field of the glass fiber reinforced thermoplastic resin composite material which uses injection molding material.

When the thermoplastic resin is a nonpolar resin such as polypropylene, a method of adding polypropylene modified with maleic acid, maleic anhydride or the like is known.

For example, as disclosed in Japanese Patent Application Laid-Open No. 48-68640 or Japanese Patent Application Laid-Open No. 51-10265, the modified polypropylene and glass fibers may be melt-kneaded and uniformly dispersed by using an extruder such as a screw. Adhesion between the interface of polypropylene and polypropylene is improved to obtain a composite material having high strength and high elastic modulus.

However, in the production of the stamping molding material obtained by the papermaking method, these prior arts cannot be applied because they do not have a step of melt-kneading the thermoplastic resin and the glass fiber.

In addition, even if the modified polypropylene additive is added to the dispersion, there is no mixing and kneading step, so that the adhesion or wettability of the interface between the glass fiber and the thermoplastic resin is insufficient, and the improvement in strength is small or the variation in strength is large.

In addition, when the additive is colored, there is a problem such as color staining on the sheet surface due to the dispersion of the additive.

In order to uniformly disperse the modified polypropylene, finely pulverizing them may cause problems such as omission from the porous support or clogging of pores during papermaking.

In addition, the modified polypropylene is also used in the above-described prior art, for example, in Japanese Patent Application Laid-Open Nos. 48-68640 or 51-10265, for example, using an extruder such as a screw to uniformly disperse the resin and the glass fibers in a melt-mixed dough. In the case of adding an additive that contributes to the adhesion of an interface such as the above, the adhesion of the interface according to the increase in the amount of addition, that is, the improvement of the mechanical properties of the composite material, whereas the decrease in the mechanical properties of the matrix resin due to the rigidity of the additive itself Inevitably, the amount of additives is inevitably limited, and the mechanical properties of the composites are not significantly improved.

In the stamping molding material using the papermaking method, even in the case of using a modified resin in advance as particles of the thermoplastic resin for molding the matrix resin, it is contrary to the adhesion of the interface according to the increase in the amount of modification, that is, the improvement of the mechanical properties after adhesion. Since the mechanical properties of the matrix resin are deteriorated due to the stiffness of the modified thermoplastic resin itself, the mechanical properties of the stamping material are not significantly improved.

SUMMARY OF THE INVENTION The object of the present invention is to solve the above problems and to improve the wettability and adhesion of conventional stamping molding materials by papermaking levers, and in particular to bond the functional groups (additives due to the adhesion of the interface) that can be combined with the silane coupling agent. The present invention provides a new stamping molding material and a method for producing the same, which exhibit maximum maximal expression, and do not cause problems such as color stains, and which have excellent fluidity and improved mechanical properties.

The present inventors have diligently studied to solve the above-mentioned problems. As a result, the present inventors supplyed a liquid containing a dispersion of reinforcing glass fibers and granular thermoplastic resin in a surfactant-containing aqueous medium in which air bubbles are dispersed on a porous support. In a stamping molding material obtained by obtaining a web and applying heat and pressure to the sheet to solidify the sheet into a sheet, the reinforcing glass fiber is treated with a silane coupling agent, and the ratio of the web to the stamping molding material of the reinforcing glass fiber is used. Preferably it is 20-70 weight%, and the matrix resin in a steaming molding material contains the functional group couple | bonded with this silane coupling agent. The matrix resin also has a special functional group gradient where the number of functional groups is in contact with the tempered glass fiber surface, and the number of functional groups gradually decreases away from the surface toward the matrix resin. Thus, excellent stamping molding materials having remarkably excellent mechanical properties were obtained.

In addition, the average 3.0x10 ¹⁷ the number of functional groups bonded with the silane coupling agent with respect to the matrix resin of the stamped and formed material - is preferably adjusted to contain 6.0x10 ¹⁹ gae / g (the functional group number / weight of the matrix resin).

In addition, the portion close to the surface of glass fiber for reinforcement is the functional group with less than 10 times the average number of functional groups of the matrix resin, and 3.0x10 ¹⁹ - it is preferable to adjust so as to contain in the range of 1.2x10 ²¹ gae / g.

By the way, the portion close to the surface of the glass fiber refers to a portion within 10 μm from the surface of the fiber, but the concentration of the functional group may be increased to a range of about 50 μm. In general, it is preferable to increase the concentration to about 30 μm.

In the present invention, the thermoplastic resins are interpolymers, graft compounds and mixtures based on polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyethylene, terephthalate, polycarbonate, polyamide, polyacetal, and resins thereof. Examples thereof include ethylene-vinyl chloride interpolymers, ethylene-vinyl acetate interpolymers, styrene-butadiene-acrylonitrile interpolymers, and the functional group is preferably at least one of an acid anhydride group, a carboxyl group, and a hydroxyl group.

In addition, as a method of manufacturing a stamping molding material having excellent mechanical properties, an aqueous solution of reinforced glass fibers and granular thermoplastic resin dispersed in a surfactant-containing aqueous medium in which air bubbles are dispersed is supplied onto a porous support sheet. In the manufacturing method of obtaining a stamping molding material obtained by applying heat and pressure to the web and solidifying the sheet into a sheet, the reinforcing glass fiber is surface treated with a silane coupling agent, and the reinforcing glass fiber is applied to the stamping molding material. The functional group is preferably 20 to 70% by weight, and the functional group capable of bonding with the silane coupling agent on the surface of the thermoplastic resin (hereinafter referred to as thermoplastic resin A) which does not contain a functional group capable of bonding with the granular silane coupling agent in the molecule. Highly mechanical properties when the thermoplastic resin (hereinafter referred to as thermoplastic resin B) in the molecule is fused Leading to the discovery by the fact that the material is obtained to achieve a manufacturing method of the present invention.

It is considered that the thermoplastic resin B containing the functional group is preliminarily fused to the thermoplastic resin A containing no functional group, and the interface between the glass fiber and the thermoplastic resin is uniformly wetted and bonded when the sheet is formed, thereby improving the adhesive strength of the interface.

In the method of directly injecting a thermoplastic resin containing a functional group into the dispersion tank, when the sheet is formed, the wettability and adhesion of the interface are uneven, so that the effect of improving the strength is small.

In addition, as another method for producing a stamping molding material having excellent mechanical properties, the web is impregnated into a thermoplastic resin (hereinafter referred to as thermoplastic resin C) having a particle diameter of 2 μm or less containing a functional group in a molecule capable of bonding with a silane coupling agent, Thereafter, even when heat and pressure were applied to the web and the sheet solidified into a sheet, it was found that a stamping molding material having excellent mechanical properties was obtained and the manufacturing method of the present invention was achieved.

When the emulsion of resin C is impregnated on the web by applying or spraying, the adhesion of resin C emulsion to the glass fiber surface or sheeting is considered to improve the wettability and adhesion between the glass fiber and the interface and to improve the strength.

In addition, it was found that the improvement in strength is particularly large when the particle size of the emulsion is 2 µm or less. This is considered to be due to the uneven adhesion of the emulsion to the glass fiber when the particle size is large and the effect of improving the strength is small.

It was found that by using these manufacturing methods in combination, thermoplastic resins A, B and C were mixed to obtain a stamping molding material with better mechanical properties.

According to the production method of the present invention, in the number of functional groups in the matrix resin, the number of functional groups that can be bonded to the silane binder in the portion close to the glass fiber surface is the largest, while the portion away from the glass fiber surface, that is, inside the matrix resin It is possible to produce stamping molding materials having a functional group gradient in which the number of functional groups gradually decreases.

Further, it contained in the matrix resin in these production methods, and the number of functional groups bonded with a silane coupling agent mean 3.0x10 ¹⁷ - it is preferable to adjust within a range of 6.0x10 ¹⁹ gae / g (the functional group number / weight of the matrix resin).

In addition, the average number of functional groups of the functional group-containing resin emulsion to be impregnated into the functional group-containing thermoplastic resin B or webs of fusing the thermoplastic resin particles of the thermoplastic resin C is 3.0x10 ¹⁹ - 1.2x10 ²¹ gae / g (number of functional groups / the thermoplastic resin B or Weight of C).

Moreover, it is preferable that all these thermoplastic resins are polypropylene, and a functional group is any of an acid anhydride group, a carboxyl group, and a hydroxyl group.

Next, the present invention will be described in more detail. First, the reinforced glass fiber is demonstrated.

In terms of obtaining sufficient reinforcing effect of the glass fibers and securing fluidity in forming the stamping molding material, the average length of the glass fibers is preferably 6-50 mm.

If the glass fiber is too short, sufficient reinforcing effect will not be obtained, and even if it is too long, fluidity at the time of molding will fall. In addition, the average fiber diameter is preferably 5-30㎛ in terms of securing the reinforcing effect of the glass fiber.

Glass fibers are preferably used so that the weight ratio of glass fibers to thermoplastic resin (glass fiber / thermoplastic) in the stamping molding material is from 20/80 to 70/30. Less glass fiber has less reinforcing effect. When excessive, it is difficult to uniformly impregnate the thermoplastic resin in the glass fiber and generate voids in the stamping molding material, resulting in deterioration of mechanical properties.

The surface of the glass fiber needs to be treated with a silane coupling agent and a sizing agent if necessary.

The silane coupling agent is used to improve the wettability or reactivity of the functional group-containing thermoplastic resin described later, and the surface improving agent is to control the surface state of the glass fiber.

As the silane coupling agent, vinyl silane, amino silane, epoxy silane, methacryl silane, chlorosilane, mercapto silane and the like can be used, and amino silane and epoxy silane are particularly preferred.

The treatment method of the silane coupling agent may be a dry method of spraying the silane coupling agent aqueous solution while mixing the glass fibers, a spraying method of spraying the silane coupling agent aqueous solution to the high temperature glass fiber, and immersion in the silane coupling agent solution. have. The amount of the silane coupling agent is preferably 0.001-0.3% by weight based on the glass fiber. More preferably, it is 0.005-0.2 weight%.

If the silane coupling material is within this range, the desired effect can be obtained within the content range of the functional group of the thermoplastic resin described later.

If it is less than 0.001% by weight, there is little improvement in mechanical properties, and if it exceeds 0.3% by weight, the operability at the time of compounding the glass fiber may be deteriorated.

The form of the reinforcing glass fibers may be one of opening of fibers or a fiber bundle of a plurality of glass short fibers, or a mixture of short fibers and fiber bundles.

When the fiber is opened, it can be controlled by adjusting the type or amount of surface improving agent.

When fiber bundles are used as reinforcing glass fibers, surface improvers which are water-soluble or virtually insoluble in surfactant-containing aqueous media are required to avoid opening during processing.

These improvers include epoxy, urethane, polyolefin, melamine and the like.

The amount of the improver is preferably 0.1 to 1.5% by weight, more preferably 0.2 to 1.3% by weight relative to the glass fiber. If it is less than 0.1% by weight, it is easy to open into short fibers in the papermaking process, and if it is more than 1.5% by weight, the wettability or adhesion between the silane coupling agent and the functional group-containing thermoplastic resin (thermoplastic B.C) may be reduced.

Some reinforcing glass fibers have a tendency to open into filaments to be treated with a water-soluble improver. Examples of these improving agents include polyethylene oxides and polyvinyl alcohols. The amount of the improver is preferably 0.03-0.3% by weight, more preferably 0.05-0.2% by weight relative to the glass fiber.

If it is less than 0.03% by weight, it can be opened before being introduced into an aqueous medium, thereby degrading operability. If it is more than 0.3% by weight, it is difficult to open in a papermaking process.

The use of fiber bundles as reinforcing glass fibers is intended to increase the flowability of the matrix resin and to increase the formability of the stamping molding material. However, if the number of fiber bundles is too large, the outer surface area of the entire glass fiber may be reduced, which may lower the mechanical strength of the stamping molding material.

Next, a thermoplastic resin is demonstrated.

Thermoplastic resins (thermoplastic resins A) include polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyethylene terephthalate, polyamide, polyacetal, and the like, and interpolymers, graft compounds and mixtures mainly composed of these resins, for example Ethylene-vinyl chloride interpolymers, ethylene-vinyl acetate interpolymers, styrene-butadiene-acrylonitrile interpolymers, and the like, among which polypropylene is preferred.

As the thermoplastic resin (thermoplastic resin B, thermoplastic C) containing the functional group bondable to the above-mentioned silane coupling agent in a molecule, one modified by various compounds such as acid and epoxy is used.

As a thermoplastic resin, for example, polypropylene can be modified with maleic acid, maleic anhydride, acrylic acid, and the like, and functional groups are suitably used as acid anhydride groups or carboxyl groups. In addition, a functional group can be suitably used by modifying the acid-modified product into various compounds or polymerizing vinyl acetate and then gelling it.

Moreover, what modified | denatured with acrylamide, methacrylamide, etc., and whose functional group was an amino group can also be used. The other functional group may be aziridine-based, epoxy-based, silane-based or the like.

The coupling between the silane coupling agent and the functional group may be any one of hydrogen bond and covalent bond, and any bond that contributes to improving the bond between the reinforced glass fiber treated with the silane coupling agent and the matrix resin is included.

The content of the functional group is 3.0x10 ¹⁷ with respect to the matrix resin is in the range of 3.0x10 ¹⁹ gae / g - 6.0x10 ¹⁹ gae / g preferably in the range of (the functional group number / weight of the matrix resin), and more preferably 1.2x10 ^18. In the case of less than 3.0x10 ¹⁷ pieces / g, the adhesion between the glass fiber surface and the silane coupling agent is insufficient and the improvement of the mechanical properties of the stamping molding material is small.

When it exceeds 6.0x10 ¹⁹ pieces / g, the effect of improving the bond between the glass fiber and the coupling agent is saturated, and it is disadvantageous in terms of cost. In addition, the mechanical properties may be reduced by coloring of the stamping molding material and weakening of the matrix resin. have.

In the present invention, the functional groups are distributed on the surface of the glass fiber as a functional functional gradient in the form of functional groups gradually decreasing toward the inside of the matrix resin, while the number of functional groups is the most in the portion close to the glass fiber surface. Contributes to its improvement.

The state in which a functional group is distributed means the state in which the thermoplastic resin (thermoplastic resin B, thermoplastic resin C) containing a functional group exists selectively in the molecule | numerator near the surface of glass fiber for reinforcement.

As a method of ubiquitous the functional group, mixed resin particles obtained by fusing the thermoplastic resin B containing the functional group on the particle surface of the thermoplastic resin A having no functional group as a component of the web, or the functional group-containing thermoplastic resin in the obtained web Emulsions of C may be sprayed or these two methods may be used in combination.

In terms of producing the web according to the papermaking method, particulate thermoplastic resin A is used.

Even when the thermoplastic resin B is fused to the particle surface of the thermoplastic resin A, the obtained composite resin should be particulate.

The particle | grains of thermoplastic resin A may use the particle | grains after superposition | polymerization, the particle | grains obtained by dissolving pellet type resin after dissolving in a solvent (chemical grinding), or the particle | grains obtained by mechanical grinding may be used. The particle diameter of the composite resin is preferably 50-2000 탆. If the particle diameter is too large, the impregnability of the resin to the glass fiber is lowered, if the particle diameter is too small, the pressure loss of the dehydration process appears in the web production method described later, and thus may cause manufacturing problems.

As a method of pre-fusion bonding the thermoplastic resin B to the particles of the thermoplastic resin A, the mixture is stirred by a Henschel mixer or the like at a temperature lower than the melting point or softening point of the thermoplastic resin A and lower than the melting point or softening point of the thermoplastic resin A.

The melting point or softening point of the thermoplastic resin B may be lower than the melting point or softening point of the thermoplastic resin A.

Fused amount of the thermoplastic resin B is the number of functional groups in the final matrix resin average 3.0x10 ¹⁷ - good or be adjusted to a range of 6.0x10 ¹⁹ gae / g (the functional group number / weight of the matrix resin), a preferred amount of fusion [(thermoplastic The weight of resin B) / (total weight of matrix resin)] x100 is in the range of 0.1-5.0 weight%.

If it is less than 0.1% by weight, it is difficult to fuse uniformly to all glass fiber surfaces, and if it exceeds 5.0% by weight, the thickness of thermoplastic resin B that is fused to the glass fiber surface becomes large, resulting in a decrease in strength due to a decrease in the mechanical properties of the matrix resin. May cause

Next, the thermoplastic resin C to be impregnated into the web as an emulsion is described.

A resin emulsion is a stable dispersion of high molecular materials in an aqueous medium. The particle diameter of the emulsion is limited to 2 μm or less, more preferably 1 μm or less in order to make the adhesion to the glass fiber uniform.

When the particle diameter is larger than 2 μm, adhesion to the glass fiber becomes uneven and wettability and adhesion are not sufficiently improved, and it is difficult to distribute many functional groups on the surface of the glass fiber. It is not exerted.

As a method of impregnating an emulsion into a web, there exists a method of spraying with a curtain coater, a spray, etc.

The addition amount of the emulsion is preferably a value of [(Amount of resin in emulsion) / (Amount of glass fibers)] × 100, in particular 0.1-2% by weight, more preferably 0.3-1.5% by weight.

If it is less than 0.1% by weight, the wettability and adhesiveness may be insufficient, resulting in less improvement in strength.

When it exceeds 2% by weight, the amount of distribution on the glass fiber surface of the thermoplastic resin C increases, resulting in a decrease in mechanical properties.

Suitable molecular weights of thermoplastic resin A containing no functional groups in the molecule range from 30,000-500,000 in weight average molecular weight.

When the weight average molecular weight is less than 30,000, the melt viscosity is low and the wettability of the glass fiber is high, but it is weak, so the mechanical properties of the stamping molding material are not excellent. In addition, when the weight average molecular weight exceeds 500,000, the melt viscosity is high and the fluidity during molding of the stamping molding material is lowered.

In addition, the impregnability of the thermoplastic resin to the glass fiber may be lowered, and the mechanical properties of the stamping molding material may be lowered as in the case where the glass fiber is excessively blended. A particularly preferred weight average molecular weight is in the range of 50,000-200,000.

The thermoplastic resin B and the thermoplastic resin C containing the functional group of the thermoplastic resin A and the functional group in the molecule are preferably the same resin. In addition, even in the case of different kinds of resins, it is preferable to show compatibility with each other.

If the compatibility between the thermoplastic resin A and the thermoplastic resin B or the thermoplastic resin C is poor, the mechanical properties of these matrix resins decrease and the mechanical properties of the product also decrease. In addition, the molecular weight of the thermoplastic resin B and the thermoplastic resin C is preferably in the range of 5,000-150,000 in weight average molecular weight.

If the weight average molecular weight is less than 5,000, it is weak as described above, the mechanical properties of the stamping molding material is low. When the weight average molecular weight is more than 150,000, the fluidity at the time of forming the stamping molding material is lowered.

However, when the blending amount of the thermoplastic resin B and the thermoplastic resin C is extremely small, the influence of the molecular weight can be ignored. Further, the thermoplastic resin B and the content of the functional group of the thermoplastic resin C is 3.0x10 ¹⁹ - 1.2x10 ²¹ gae / g and the range of (the functional group number / weight of the thermoplastic resin B or C), more preferably 6.0x10 ¹⁹ - 6.0x10 ²⁰ pieces / g.

3.0x10 ¹⁹ gae / g, increasing the amount of the essentially weaker thermoplastic resin B or C is less than the results in a decrease in mechanical properties.

In addition, when the amount exceeds 1.2x10 ²¹ pieces / g, the compounding amount of the thermoplastic resin B or the thermoplastic resin C is inevitably reduced, the dispersion of the functional groups on the glass fiber surface is insufficient, and the improvement of the mechanical properties may be reduced.

Further, these thermoplastic resins may be composed of a plurality of thermoplastic resins having different molecular weights, types of functional groups, and functional group contents, respectively.

Next, the manufacturing method of a stamping molding material is explained in full detail. The manufacturing method of a stamping molding material is illustrated as follows.

The glass fiber chopped strand and thermoplastic resin particles or particles of a composite resin in which thermoplastic resin B is pre-fused on the surface of thermoplastic resin A are dispersed in an aqueous surfactant solution in which air bubbles are dispersed.

The dispersion can be dehydrated through a porous support to obtain a web in which thermoplastic resin particles are uniformly mixed and dispersed in glass fibers. The thickness of the web is usually 1-10 mm.

The web is then impregnated with an emulsion of thermoplastic C as needed. The web is dried and then heated above its melting point or softening point to melt the resin, sandwich it between cold plates, and apply pressure to obtain a densely molded, stamped molding material.

The heating temperature of the web needs to be set below the decomposition temperature of the thermoplastic resin.

170-230 degreeC is preferable, and 190-210 degreeC is especially preferable. When it exceeds 230 degreeC, coloring and mechanical property fall by the decomposition | disassembly of polypropylene are caused.

When the web is pressed in the cold plate, the pressure is preferably 3-500 Kgf / cm 2 for densification purposes. Excessive pressure may cause glass fiber breakage.

In addition, the stamping molding material may contain an additive such as an antioxidant, a weather stabilizer, a metal inactivator, an antifreeze agent, a flame retardant agent, carbon black, or a coloring agent.

These additives, colorants, and the like can be added at the same time, for example, when the thermoplastic resin A and the thermoplastic resin B are mixed and melted, or added by spray or the like during the stamping molding material manufacturing process to be contained in the stamping molding material.

Finally, the molding method will be described.

The stamping molding material manufactured as described above is molded by a known method.

That is, the stamping molding material is heated above the melting point or softening point of the thermoplastic resin and below the decomposition temperature, and then placed in a mold to press and shaping. When the thermoplastic resin is polypropylene, the heating temperature is preferably 170 to 230 ° C. Mold temperature should just be below the freezing point of a thermoplastic resin. From a viewpoint of handleability and productivity, they are room temperature to 60 degreeC normally.

The molding pressure varies depending on the product shape, but is usually 50-500 Kgf / cm 2.

In addition, although the present invention has described a stamping molding material made by the papermaking method, the idea of the present invention is not limited thereto, and may be applied to impregnating a thermoplastic resin in a glass fiber mat.

Hereinafter, the present invention will be described in more detail with reference to Examples.

Example 1-1

The following two resins were prepared as matrix resins.

Thermoplastic resin A: Polypropylene (white granule, average particle diameter 800㎛, weight average molecular weight 150,000 melting point 165 ° C)

Thermoplastic B: Maleic anhydride-modified polypropylene [Yellow, average particle diameter 2mm, maleic anhydride modification amount 10.0% by weight (6.0 x 10 ²⁰ acid anhydride groups / g, carboxyl groups resulting from hydrolysis of acid anhydride groups are converted to acid anhydrides) , Weight average molecular weight 12,000 melting point 142 ℃]

96.5 parts by weight of particles of thermoplastic resin A and 3.5 parts by weight of particles of thermoplastic resin B were mixed in a Henschel mixer (201 Mitsuiichi Kogyo Co., Ltd.) and mixed under heat treatment at a circumferential speed of the stirring blades for 25 minutes at 25 m / s for a maximum of 142 ° C. The mixture was stirred to obtain a composite resin particle having an average particle size of 800 µm in which thermoplastic resin B was fused in a film form to thermoplastic resin A particles.

The composite resin particles (the number of acid anhydride groups in the matrix resin 2.1x10 ¹⁹ / g) contains 33.75g, 13mm average fiber length, 10μm glass fiber chopped strand (containing 0.06% by weight of aminosilane coupling agent) ) 22.50 g (40% by weight of glass fibers in the stamping molding material) was stirred and bubbled in 10 l of a 0,8% by weight aqueous solution into a paper machine with a paper surface area of 250x250mm. Degassing yielded a 900 g / m 2 web.

Then, it dried at 90 degreeC for 90 minutes, and similarly manufactured three 900 g / m <2> webs again.

Four webs were laminated, preheated at 210 ° C., placed between 25 ° C. cold plates, and pressed at a pressure of 5 kgf / cm 3 to obtain a compacted glass fiber reinforced thermoplastic resin composite material (stamping molding material).

From the center of the stamping molding material, a bending test piece was made according to JIS K7055, and a bending test was performed on three samples to measure the bending strength. The results are shown in the first table.

In addition, the obtained stamping molding material was cut at an angle with respect to the orientation axis of the glass fiber for reinforcement to obtain a thin film, and a microscopic 1R (Fourier Transform Infrared Spectrophotometer Micro FTIR-100 type, Nippon Bunko Kogyo Co., Ltd.) was applied to the thin film. was used to measure the absorption band (1785㎝ ^-1) concentration of the functional group with respect to the matrix resin from the absorption band (1710㎝ ^-1) derived from a carboxyl group derived from the acid anhydride groups (comparison with CH out-of-plane vibration byeongak 840㎝ ^-1) .

The functional range was measured at a position of about 25 mu m square (about 10 mu m in terms of vertical distance from the glass fiber surface) and 10 mu m away from the matrix resin close to the glass fiber surface. The results are shown in the second table.

Comparative Example 1-1

A stamping molding material was obtained in the same manner as in Example 1-1 except that 33.75 g of the thermoplastic resin A particles were used instead of the composite resin without performing the process of fusion bonding the thermoplastic resin B to the thermoplastic resin particles.

In addition, as in Example 1-1, the results of measuring the bending strength, the flexural modulus, and the functional number are shown in the first and second tables. In addition, the flexural strength in this case is shown in FIG. 1 and FIG. Represented.

Example 1-2

A stamping molding material was obtained in the same manner as in Example 1-1 except that the following materials were used as the thermoplastic resin B.

Thermoplastic B: Maleic anhydride modified polypropylene [Yellow, average particle diameter 2mm, maleic anhydride modification amount 5.0% by weight (3.0x10 ²⁰ acid / anhydride group number, carboxyl group formed by hydrolysis of acid anhydride group) Weight average molecular weight 27,000 melting point 151 ℃]

Flexural strength, flexural modulus, and functional number were measured in the same manner as in Example 1-1. The color of the sheet surface was also observed. The results are shown in the first and second tables.

Comparative Example 1-2

Stamping molding was carried out in the same manner as in Example 1-2 except that 32.57 g of the thermoplastic resin A and 1.18 g of the thermoplastic resin B were used instead of the composite resin without the process of fusion bonding the thermoplastic resin B to the particles of the thermoplastic resin A. Obtained the material. In addition, flexural strength, flexural modulus, and functional number were measured as in Example 1-2. The results are shown in the first and second tables.

Comparative Example 1-3

These resins are pre-melted and kneaded (using a twin-screw extruder, mixing dough temperature 200 ° C, residence time 1 minute) without grinding the thermoplastic resin B to the particles of the thermoplastic resin A, and then pulverized. The stamping molding material was obtained like Example except having obtained and using this mixed resin.

Flexural strength, flexural modulus, and average functional number were measured as in Example 1-2. In addition, the color of the sheet surface was observed.

Example 1-3

A stamping molding material was obtained in the same manner as in Example 1-1 except that the following materials were used as the thermoplastic resin B.

Thermoplastic B: Maleic acid modified polypropylene [sulfuric acid, average particle diameter 2mm, maleic acid modification amount 5.0% by weight (5.1x10 ²⁰ carboxyl groups / g), weight average molecular weight 27,000 melting point 151 ℃]

Flexural strength, flexural modulus, and functional number were measured as in Example 1-1. The color of the sheet surface was also observed. The results are shown in the first and second tables.

It can be seen from this example that a stamping molding material having a large number of functional groups in the matrix resin is unevenly distributed on the surface of the glass fiber and gradually reduced in the matrix resin.

In addition, it can be seen that this stamping molding material has high flexural strength, flexural modulus and small fluctuation range.

Compared with the comparative example in which the thermoplastic resin A and the functional group-containing thermoplastic resin B were simply mixed, a sheet of good appearance was obtained, in which the mechanical properties were improved and the coloring of the addition of the thermoplastic resin B was also uniform.

In addition, the mechanical properties of the thermoplastic resin A and the functional group-containing thermoplastic resin B are better than those of the mixed resin obtained by melt-kneading in advance.

Example 2-1

The following two resins were prepared as matrix resins.

Thermoplastic resin A: Polypropylene (white granule, average granule 800㎛, weight average molecular weight 150,000 melting point 165 ° C)

Thermoplastic resin C: Emulsion of maleic anhydride-modified polypropylene [active ingredient 0.5% by weight, solid yellow, average particle size 0,8㎛, maleic anhydride modification amount 10.0% by weight (acid anhydride number 6.0x10 ²⁰ pieces / g, acid anhydride group) Carboxyl group resulting from hydrolysis is converted to acid anhydride) weight average molecular weight 12,000 softening point 142 ℃]

33.75 g of thermoplastic resin A, 13 mm of average fiber length, and 10 μm of average fiber diameter, 22.50 g of glass fiber chopped strand (containing 0.06% by weight of aminosilane coupling agent) (40% by weight of the glass fiber in the stamping molding material) The dispersion liquid stirred and bubbled in 10 L of surfactant and 0.8 weight% aqueous solution was put into the paper machine of the paper area of 250x250 mm, and it was aspirated and degassed, and the web of 900 g / m <2> was produced.

Subsequently, this web was impregnated with a spore spray of 67.50 g of an emulsion of thermoplastic resin C [(The conversion of the emulsion into the web was 100%. The total number of functional groups (acid anhydride groups) in the matrix resin was 3.7 × 1 ¹⁸ . / g] It was then dried for 90 minutes at 130 ℃.

Similarly, three 900g / m webs were prepared again, and four webs were laminated, preheated to 210 ° C, placed between 25 ° C cold plates, and pressed at a pressure of 5 kgf / cm 3 to form a solid stamping molding material. Got.

Flexural strength, flexural modulus, color of the sheet and the number of functional groups were measured in the same manner as in Example 1-1. The results are shown in Tables 3 and 4.

Example 2-2

A stamping molding material was obtained in the same manner as in Example 2-1, except that the following materials were used as the emulsion of the thermoplastic resin C.

Thermoplastic C: Emulsion of maleic acid-modified polypropylene [active ingredient 0.5%, solid content yellow, average particle diameter 0.2㎛, maleic acid modification amount 5.0% by weight (carboxylic acid number 5.1x10 ²⁰ pieces / g], weight average molecular weight 27,000 softening point 151 ° C]

Flexural strength, flexural modulus, sheet color and functional number were measured in the same manner as in Example 2-1. The results are shown in Tables 3 and 4.

Comparative Example 2-1

Stamping was carried out in the same manner as in Example 2-2, except that 0.34 g (corresponding to the same formulation as that of the thermoplastic resin C of Example 2-2) was used together with the thermoplastic resin A without using the thermoplastic resin C as an emulsion. Molding material was obtained.

Flexural strength, flexural modulus, color of sheet and functional number were measured in the same manner as in Example 2-2. The results are shown in Tables 3 and 4.

Comparative Example 2-2

A stamping molding material was obtained in the same manner as in Example 2-2 except that the thermoplastic resin C was used as an emulsion and changed to that of an average particle diameter. Flexural strength, flexural modulus, and color of the sheet were measured in the same manner as in Example 2-2. The results are shown in Table 3.

Also in this example, a stamping molding material was obtained, characterized in that the number of functional groups in the matrix resin gradually decreased from the glass fiber surface toward the inside of the matrix resin. In addition, it can be seen that this stamping molding material has a high flexural strength, a flexural modulus and a small variation.

Compared with the comparative example in which the thermoplastic resin A and the functional group-containing thermoplastic resin C were simply particle-mixed, a sheet having a large improvement in mechanical properties and less coloring due to the addition of the thermoplastic resin C and having a uniform color was obtained.

In addition, when the particle size of the emulsion is excessive, there is little improvement in mechanical properties.

Example 3

The following three resins were prepared as matrix resins.

Thermoplastic A: Polypropylene (weight average molecular weight 150,000 melting point 165 ° C)

Thermoplastic resin B: Maleic anhydride modified polypropylene [10.0% by weight of maleic anhydride modifying group ( ²⁰ acidic anhydride groups 6.0x10 / g. Carboxyl group resulting from hydrolysis of acid anhydride group) converted to acid anhydride) Weight average molecular weight 32,000 Melting point 142 ° C ]

Thermoplastic Resin C: The same resin as the thermoplastic resin B was used as an emulsion having a particle size of about 0.8 m and an active ingredient of 5.0% by weight.

96.8 parts by weight of particles of thermoplastic resin A and 3.2 parts by weight of particles of thermoplastic resin B were introduced into a Henschel mixer and mixed and stirred while heated to 142 ° C. A micrometer composite resin particle was obtained.

22.50 g of the glass fiber chopped strand (containing 0.06% by weight of an aminosilane coupling agent) having 30.0 g of this composite resin particle, an average fiber length of 13 mm, and an average fiber diameter of 10 µm (40% by weight of the glass fiber in the stamping molding material) The dispersion liquid stirred and bubbled in 10 L of surfactant and 0.8 weight% of sodium dodecylbenzene sodium sulfonate aqueous solution was adjusted to the paper machine of 250 x 250 mm of paper area, and aspirated and degassed, and the web of 900 g / m <2> was produced.

This web was then impregnated with a spray spray of 15.00 g of an emulsion of thermoplastic resin C. [(The total number of the total amount of the functional group (acid anhydride + carboxyl group) in which the conversion rate of the emulsion into the web is in the 100% matrix resin is 2.0x10 ¹⁹ pieces / g] Then, it dried at 130 degreeC for 90 minutes.

Similarly, three 900g / m² webs were prepared again, and four webs were laminated, preheated to 210 ° C, placed between 25 ° C cold plates, pressed at a pressure of 5kgf / cm3, and molded into a solid glass fiber reinforced thermoplastic resin. A composite material (stamping molding material) was obtained.

Flexural strength and functional number were measured in the same manner as in Example 1-1. The average functional group was calculated from the results and shown in Table 5.

The functional groups in the matrix resin are widely distributed on the surface of the glass fiber, and are present in the portion close to the glass fiber of 10 times or more of the average functional group (20x10 ¹⁸ pieces / g) in the matrix resin. In addition, it was confirmed that the functional number gradually decreased as the distance from the surface.

In addition, the thermoplastic resin B and the thermoplastic resin C are increased or decreased at the same ratio, and the number of functional groups [acid anhydride groups] in the matrix resin is adjusted to be within the range of 3.0x10-1.2x10 pieces / g (weight of functional group / matrix resin). A stamping molding material was produced as described above except that the same evaluation was made.

The relationship between the average number of functional groups and the flexural strength of the matrix resin was investigated. The results are collected and shown in FIG.

Comparative Example 3

As a reinforcing glass fiber, a stamping molding material was produced in the same manner as in Example 3 except that glass fiber chopped strands not treated with an aminosilane coupling agent were used for the same evaluation. The results are shown in FIG. In addition, this figure also showed the case where a functional group was not added.

Example 3-1

The following two glass fibers were prepared as glass fiber chopped strands.

Glass fiber chopped strand A (same as the glass fiber of Example 3): average length 13mm, average fiber diameter 10㎛, aminosilane coupling agent 0.06% by weight, polyethylene oxide-based improver 0.05% by weight, number of belonging 5000 pieces / speed.

Glass fiber chopped strand B: average length 13mm, average fiber diameter 10㎛, 0.1% by weight of the aminosilane coupling agent, 1.9% by weight of the urethane-based improver, the number of procedures 70 / speed.

In addition, glass fiber chopped strand A was opened as short fibers in the papermaking process, while glass fiber chopped strand B retained its original strand shape.

For example, when the average number of functional groups in the matrix resin in Example 3 is 2.0x10 ¹⁹ pieces / g, for example, instead of the glass fiber for reinforcement used at this time, 11.25 g of glass fiber strand strand A and 11.25 g of glass fiber strand strand B are used. In the same manner, a stamping molding material was manufactured and a bending test was performed.

The flexural strength, the flexural modulus results, and the opening state of the glass fibers are shown in Table 6.

Example 3-2

For example, the average number of functional groups on the matrix resin in Example 3 is 2.0x10 ¹⁹ pieces / g. For example, instead of using the glass fiber for reinforcement used at that time, except that 22.5 g of glass fiber chopped strand B is used, the stamping molding material is the same. Was prepared and subjected to the bending test.

The results of the bending strength, the flexural modulus, and the opening state of the glass fiber are shown in Table 6.

Even when the opening state of the glass fiber was changed, the stamping molding material of the present invention exhibited high mechanical properties. In addition, when the obtained glass fiber is used, the flowability of the stamping molding material, that is, the moldability is improved as the ratio of the glass fiber bundle increases.

Example 4

The following three resins were prepared as matrix resins.

Thermoplastic A: Polypropylene (weight average molecular weight 150,000 melting point 165 ° C)

Thermoplastic B: Hydroxyl Modified Polypropylene [hydroxyl number 6.8x10 ^-4 mol / g, weight average molecular weight 45,000 melting point 152 ° C]

Thermoplastic resin C: emulsion of maleic anhydride-modified polypropylene [10% by weight of maleic anhydride modification amount (carboxyx group resulting from hydrolysis of acid anhydride number 6.0x10 / g acid anhydride group) to acid anhydride group, carboxyl group 2.0x10 ^-4 mol / g (molar number of carboxyl groups / weight of maleic anhydride modified polypropylene), weight average molecular weight 32,000 melting point 142 ° C., average particle size about 0.8 μm, active ingredient 5.0 wt%]

94.7 parts by weight of particles of thermoplastic resin A and 5.3 parts by weight of particles of thermoplastic resin B were introduced into a Henschel mixer, mixed and agitated under heat treatment at 152 ° C., and the average particle diameter of thermoplastic resin B was fused to the particles of thermoplastic resin A in a membrane shape. A micrometer composite resin particle was obtained.

20.00 g of glass fiber chopped strand (containing 0.08% by weight of epoxy silane coupling agent) of 30.00 g of this composite resin particle, average length of 13 mm, average fiber length of 13 mm, and average fiber particle diameter of 10 µm (weight of glass fiber in stamping molding material 40 wt%) was stirred and bubbled in 10 liters of a 0.8 wt% aqueous solution of a surfactant and placed in a paper machine having a paper area of 250 × 250 mm, followed by suction defoaming to prepare a web of 900 g / m 2.

Subsequently, this web was impregnated with a spray spray of 15.00 g of an emulsion of thermoplastic resin C. [The conversion rate of the emulsion into the web was 100%, and the total amount of functional groups (hydroxyl + acid anhydride groups) in the matrix resin was 2.2x10 ¹⁹ pieces / g]. Then, it dried at 130 degreeC for 90 minutes.

Similarly, three 900g / m 2 webs were prepared again, the webs were laminated, preheated to 210 ° C., placed between the cold plates at 25 ° C., and pressed at a pressure of 5 kgf / cm 3 to form a compacted glass fiber reinforced thermoplastic resin composite material ( Stamping molding material).

From the center of the stamping molding material, a bending test piece was made according to JIS K7055, a three-point bending test was performed, and the bending strength was measured.

In addition, it is increasing or decreasing the thermoplastic resin B and the thermoplastic resin C at the same rate and the number of 3.0x10 ¹⁷ of the functional group (hydroxyl group + acid anhydride group) which points in the matrix resin - a range of 1.2x10 ²⁰ gae / g (the functional group number / weight of the matrix resin) A stamping molding material was produced and evaluated in the same manner as described above except that it was adjusted to be inside. The relationship between the average number of functional groups and the bending strength in the matrix resin was investigated. The results are collected and shown in FIG.

[Comparative Example 4]

As a reinforcing glass fiber, a stamping molding material was produced in the same manner as in Example 4 except that glass fiber chopped strands not treated with an epoxy silane coupling agent were used, and the same evaluation was performed. The results are collected and shown in the second table.

This figure also shows the case where no functional group was added.

The thermoplastic resin B and the thermoplastic resin C are added to the matrix resin to contain a functional group capable of bonding with the silane coupling agent, thereby greatly improving the bending strength. However, when the amount thereof is insufficient or excessive, the improvement in bending strength is small.

Thermoplastic resins A, B, and C are used in combination to form high flexural strength as shown in the examples.

In the presence of the glass fibers treated with a silane coupling agent to the number of functional groups that the matrix resin 3.0x10 ¹⁷ - 6.0x10 ¹⁹ gae / g (the functional group number / weight of the matrix resin) range, in particular of ¹⁸ 3.0x10 - 4.0x10 ¹⁹ gae Flexural strength is maximized within the range of / g.

Example 5

For example, the average number of functional groups on the matrix resin in Example 3 is 2.0x10 ¹⁹ pieces / g. For example, except that the weight of the glass fibers on the stamping molding material is changed to the range of 5-80% by weight, the stamping is performed in the same manner. Molding materials were prepared and the relationship between the weight and the flexural strength of the glass fibers in the stamping molding materials was investigated. The results are shown in FIG.

[Comparative Example 5]

The relationship between the weight and the bending strength of the glass fibers in the stamping molding material was investigated without using the thermoplastic resins B and C and the matrix resin as the total thermoplastic resin A. The results are shown in FIG.

From these results, in the case of the present invention, high flexural strength is expressed when the weight ratio of the glass fiber to the stamping molding material is 20 to 70% by weight.

In addition, the stamping molding material that satisfies the present invention has no problem in forming a bumper beam having excellent fluidity.

According to the present invention as described above, it is possible to provide a stamping molding material and a material method excellent in mechanical properties such as bending strength.

For this reason, it can be usefully used as a structural member which requires high strength and high rigidity, for example, an automobile member, such as a bumper beam.

Claims (8)

The glass fiber for reinforcement and the granular thermoplastic resin are dispersed in a surfactant-containing aqueous medium in which air bubbles are dispersed, and the dispersion is brought into contact with a porous support to obtain a sheet-like web, which is heated and pressurized into a sheet form. In the molding solidified molding material, the glass fiber for reinforcement is treated by at least one method selected from the group consisting of a dry method, a spray method, and a immersion method using a silane coupling agent, and 20 to 70 weight of the total molding material. It is contained in the composition of%, the matrix resin contained in the stamping molding material at least one functional group selected from the group consisting of acid anhydride group, carboxyl group, hydroxyl group, epoxy group, amino group, aziridine group and silane group which is a functional group bondable with silane coupling the average 3.0x10 ¹⁷ to 6.0x10 ¹⁹ gae / g (the functional group number / weight of the matrix resin) In the portion within 50㎛ from the surface of the glass fiber for reinforcement, the functional group of 10 times or more of the average functional group contained in the matrix resin is distributed, and the functional group number gradually decreases toward the inside of the matrix resin beyond the above range. Stamping molding material with excellent mechanical properties. The functional group of claim 1, wherein the functional group contained in the matrix resin is 10 times or more than the average functional group number of the matrix resin in a portion within 50 µm from the surface of the glass fiber for reinforcement and is in the range of 3.0x10 ¹⁹ to 1.2x10 ²¹ pieces / g. Stamping molding material with excellent mechanical properties, characterized in that distributed by a number. The stamping molding material having excellent mechanical properties according to claim 1 or 2, wherein the granular thermoplastic resin is polypropylene and the functional group is at least one selected from the group consisting of an acid anhydride group, a carboxyl group and a hydroxyl group. Treated by at least one method selected from the group consisting of a dry method, a spray method and a immersion method using a silane coupling agent, having substantially 20 to 70% by weight of reinforcing glass fibers and a functional group bondable with the silane coupling agent. It has a lower melting point or softening point than the resin (A) on the surface of the granular thermoplastic resin (A), has compatibility and is selected from the group consisting of acid anhydride groups, carboxyl groups, hydroxyl groups, epoxy groups, amino groups, aziridine groups and silane groups The thermoplastic resin (B) contained in the molecule by at least one functional group in the molecule by 3.0x10 ¹⁹ to 1.2x10 ²¹ pieces / g (the number of functional groups / resin (B)) is in the range of 0.1 to 5.0% by weight with respect to the resin (A). The composite resin particles having a particle size of 50 to 2000 μm formed by fusion in advance are dispersed in a surfactant-containing aqueous medium in which air bubbles are dispersed to prepare a dispersion liquid. A method for producing a stamping molding material having excellent mechanical properties, characterized in that the dispersion is brought into contact with a porous support to prepare a sheet type web, and the web is heated and pressurized to form a sheet. Treated by at least one method selected from the group consisting of a dry method, a spray method and a immersion method using a silane coupling agent, having substantially 20 to 70% by weight of reinforcing glass fibers and a functional group bondable with the silane coupling agent. The granular thermoplastic resin (A) is dispersed in a surfactant-containing aqueous medium in which microbubbles of air are dispersed to prepare a dispersion, and the dispersion is brought into contact with a porous support to prepare a sheet-shaped web. At least one functional group selected from the group consisting of a group, a carboxyl group, a hydroxyl group, an epoxy group, an amino group, an aziridine group and a silane group is 3.0x10 ¹⁹ to 1.2x10 ²¹ pieces / g (weight of functional group number / resin (C)) in the molecule. The resin emulsion of the thermoplastic resin (C) having a particle diameter of 2 μm or less is impregnated in an amount ranging from 0.1 to 2% by weight based on the amount of glass fibers. The method of stamping molding material excellent in mechanical properties, characterized in that by pressing the web to heat the chimdoen solidified molding into a sheet. The surface of this thermoplastic resin (A) has a lower melting point or softening point than the resin (A) instead of the granular thermoplastic resin (A), and has an acid anhydride group, a carboxyl group, a hydroxyl group, an epoxy group, an amino group, an aziridine group, At least one functional group selected from the group consisting of silane groups contains thermoplastic resin (B) contained in the molecule by 3.0x10 ¹⁹ to 1.2x10 ²¹ pieces / g (weight of functional group number / resin (B)) to resin (A). Method for producing a stamping molding material having excellent mechanical properties, characterized in that the composite resin particles having a particle size of 50 to 2000㎛ formed in advance by fusion in an amount in the range of 0.1 to 5.0% by weight. The functional group contained in the matrix resin is at least one member selected from the group consisting of an acid anhydride group, a carboxyl group, a hydroxyl group, an epoxy group, an amino group, an aziridine group, and a silane group. A method of producing a stamping molding material having excellent mechanical properties, characterized in that the functional group is adjusted to contain an average of 3.0x10 ¹⁷ to 6.0x10 ¹⁹ pieces / g (the number of functional groups / matrix resin). The method of claim 4, 5 or 6, wherein the thermoplastic resins (A), (B) and (C) are all polypropylene and the functional group is at least one member selected from the group consisting of acid anhydride groups, carboxyl groups and hydroxyl groups. A method for producing a stamping molding material having excellent mechanical properties.