JP2000185357A - Manufacture of sheet-like molding material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve productivity of a sheet-like molding material, to reduce a using amount of a film, to decrease a discarding amount of the film, and to shorten a molding time by setting a thickness of the molding material to about 3 to 4 mm. SOLUTION: A mold release film is coated with a paste-like resin composition containing an unsaturated polyester resin and a polymerizable monomer, and reinforcing fibers are scattered on the composition. Further, paste-like resin composition is placed on the fibers, the fibers are uniformly coated with the composition by a blade, and the film scattered with the fibers and the release film coated with the composition are superposed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a sheet-like molding material.

[0002]

2. Description of the Related Art A conventional method for producing a sheet-like molding material is a paste containing, on a film, an unsaturated polyester resin, a thermoplastic resin, a peroxide, a polymerization inhibitor, an inorganic powder, a release agent, magnesium oxide, and the like. Apply the resin composition,
The method comprises spraying glass fibers and laminating a film coated with the paste-like resin composition. In the method for producing such a sheet-like molding material, the thickness of the obtained sheet-like molding material is limited to about 1.5 to 2 mm in order to ensure the impregnation of the paste-like resin composition into glass fibers. . For this reason, the productivity of the sheet-shaped molding material decreases. In addition, the amount of film used is large, the cost is high, and the disposal of the film after the use of molding has been a problem. Further, there is a problem that it takes time and effort to cut out a necessary amount during the molding operation.

[0003]

SUMMARY OF THE INVENTION The present invention improves the productivity of a sheet-like molding material, reduces the amount of film used, and reduces the amount of film waste by reducing the thickness of the sheet-like molding material to about 3 to 4 mm. Another object of the present invention is to provide a method for producing a sheet-like molding material capable of shortening the molding operation time.

[0004]

According to the present invention, a paste-like resin composition containing an unsaturated polyester resin and a polymerizable monomer is applied onto a release film, and reinforcing fibers are sprinkled thereon. Further, the paste-like resin composition is placed thereon, and is uniformly applied with a blade, and then a reinforcing fiber is scattered, and a release film coated with the paste-like resin composition is laminated. And a method for producing a sheet-shaped molding material.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The method for producing a sheet-shaped molding material of the present invention is based on the conventional production method in order to ensure the thickness of the sheet-shaped molding material and the impregnation of the paste-like resin composition into the reinforcing fibers.
Further, application of a paste-like resin composition and dispersion of reinforcing fibers are added. Further, it is preferable that the paste-like resin composition to be added is pressurized and discharged from a plurality of nozzles and placed on the reinforcing fiber so as to be easily applied uniformly. The paste-like resin composition is further homogenized by a blade. This makes it possible to reduce the thickness of the sheet-shaped molding material to about 3 to 4 mm while ensuring the impregnation of the paste-like resin composition into the glass fibers.

In the present invention, as the release film,
There is no particular limitation, and a polyethylene film, a polypropylene film, a polyethylene terephthalate film, or the like can be used. The paste-like resin composition used in the present invention is not particularly limited as long as it contains an unsaturated polyester resin and a polymerizable monomer. Various additives such as an agent, a filler, an internal release agent, and a thickener can be contained. The amount of each of these additives can be appropriately determined.

In the present invention, the unsaturated polyester resin is obtained by reacting a polybasic acid component containing an α, β-unsaturated polybasic acid or its anhydride as an essential component with a polyhydric alcohol. Examples of the α, β-unsaturated polybasic acid or its anhydride as the raw material for synthesis include α, β-unsaturated dibasic acid or its anhydride, for example, maleic acid, fumaric acid, itaconic acid, citraconic acid , Maleic anhydride, and anhydrides thereof. These may be used in combination of two or more. As the polybasic acid component, to adjust the concentration of the unsaturated group, flexibility, to impart properties such as heat resistance,
It is preferable to use a saturated polybasic acid or its anhydride in addition to the α, β-unsaturated polybasic acid or its anhydride. At this time, as the α, β-unsaturated polybasic acid or its anhydride,
Preferably, the content is 40 mol% or more of the polybasic acid component. When the amount of α, β-unsaturated polybasic acid or its anhydride is less than 40 mol%, the strength of the obtained molded article tends to gradually decrease. For this reason, the content of the α, β-unsaturated polybasic acid or its anhydride is more preferably from 45 to 80 mol%, particularly preferably from 50 to 70 mol%.

The saturated polybasic acid or anhydride used includes phthalic acid, phthalic anhydride, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, tetrahydrophthalic anhydride, 3,6-endomethylenetetrahydrophthalic anhydride, Hexahydrophthalic acid, hexahydrophthalic anhydride, glutaric acid, adipic acid, sebacic acid, trimellitic acid, trimellitic anhydride, pyromellitic acid, dimer acid, succinic acid, azelaic acid, rosin-maleic acid adducts, etc. Can be These may be used in combination of two or more.

Polyhydric alcohols, which are another raw material for the synthesis of unsaturated polyester resins, include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3-butanediol,
6-hexanediol, neopentyl glycol, 1,
Examples thereof include dihydric alcohols such as 4-cyclohexanediol and hydrogenated bisphenol A, trihydric alcohols such as glycerin and trimethylolpropane, and tetrahydric alcohols such as pentaerythritol. These may be used in combination of two or more.

The polybasic acid component and the polyhydric alcohol are preferably used in an equivalence ratio of 1 to 1.3 when the polybasic acid component is set to 1;
More preferably, it is used in the range of 1.05 to 1.05. When the polyhydric alcohol decreases, the molecular weight of the resulting unsaturated polyester resin tends to decrease, and when the polyhydric alcohol increases, the acid value decreases and the progress of thickening by the thickener tends to be slow.

As a method for producing the unsaturated polyester resin, a conventionally known method can be used. For example,
Condensation reaction between the polybasic acid component and the polyhydric alcohol component,
The reaction proceeds while removing condensed water generated when both components react. The removal of the condensed water out of the system is preferably performed by natural distillation or vacuum distillation by passing an inert gas. In order to promote the distillation of condensed water, a solvent such as toluene or xylene can be added to the system as an azeotropic component. The progress of the reaction can be generally known by measuring the amount of distillate generated by the reaction, quantifying the functional group at the end, measuring the viscosity of the reaction system, and the like. The reaction temperature is preferably 150 ° C. or higher, and the reaction is preferably performed while passing an inert gas such as nitrogen or carbon dioxide in order to prevent a side reaction due to oxidation.

For this reason, as the reaction apparatus, those made of glass, stainless steel or the like are selected, and a stirrer, a fractionating apparatus for preventing the alcohol component from being distilled off by azeotropic distillation of water and the alcohol component, and a reaction system are used. It is preferable to use a heating device for raising the temperature, a temperature control device for the heating device, a reaction device provided with a blowing device for an inert gas such as nitrogen, and the like.

The polymerizable monomer used in the present invention includes, for example, styrene derivatives such as styrene, chlorostyrene, divinylbenzene, tert-butylstyrene, and styrene bromide, methyl methacrylate, ethyl methacrylate, and ethyl acrylate. , Methacrylic acid or acrylic acid alkyl ester such as butyl acrylate, β-hydroxyethyl methacrylate, methacrylic acid or acrylic acid hydroxyalkyl ester such as β-hydroxyethyl acrylate, diallyl phthalate, acrylamide, phenylmaleimide and the like. Can be Polyfunctional methacrylic acid or acrylic acid esters such as ethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, and trimethylolpropane trimethacrylate can also be used.

It is preferable that the unsaturated polyester resin is mixed with a polymerizable monomer and, if necessary, a polymerization inhibitor or the like is added thereto to be used as an unsaturated polyester resin composition. At this time, the mixing ratio of the unsaturated polyester resin and the polymerizable monomer is 25 to 80 parts by weight of the unsaturated polyester resin and 75 to 75 parts by weight of the polymerizable monomer when the total amount of both is 100 parts by weight. Preferably it is 20 parts by weight. When the amount of the unsaturated polyester resin is less than 25 parts by weight, the viscosity of the unsaturated polyester resin composition is too low to be easily applied to a sheet, and it is difficult to uniformly mix with other components due to sedimentation and the like. Even when the obtained fiber-reinforced molding material is molded, the curing shrinkage is large, and the molded product may be cracked or cracked. If the amount of the unsaturated polyester resin exceeds 80 parts by weight, the viscosity may be so high that it may be difficult to apply or mix with other components. For this reason, it is more preferable that the unsaturated polyester resin is 40 to 65 parts by weight and the polymerizable monomer is 60 to 35 parts by weight.

As the low shrinkage agent, a thermoplastic resin can be used. Examples of the thermoplastic resin that can be used include thermoplastic resins conventionally used as low shrinkage agents for unsaturated polyesters, such as polystyrene, polyvinyl acetate, polymethyl methacrylate, polyethylene, and poly-
ε-caprolactam, saturated polyester, polyvinyl chloride, polybutadiene, styrene-acrylic acid copolymer,
Styrene-vinyl acetate copolymer, acrylonitrile-styrene copolymer and the like are used. These can be used alone or in combination of two or more. The low-shrinkage agent is preferably used in an amount of 20 to 50% by weight based on the total amount of the unsaturated polyester resin and the polymerizable monomer.

Examples of the curing agent include ketone peroxides, peroxydicarbonates, hydroperoxides, diacyl peroxides, peroxyketals, dialkyl peroxides, peroxyesters, and alkyl peresters. And the like. The amount of the curing agent is determined not only in the molding cycle but also in the storage stability of the material, color unevenness, and the like. The curing agent is preferably from 0.5 to 5% by weight, more preferably from 1 to 3% by weight, based on the total amount of the unsaturated polyester resin and the polymerizable monomer, from the viewpoint of the preservability of the material and the molding cycle. .

Examples of the polymerization inhibitor include p-benzoquinone, hydroquinone, naphthoquinone, p-toluquinone, 2,5-diphenyl-p-benzoquinone, 2,5-
Diacetoxy-p-benzoquinone, p-tert-butylcatechol, 2,5-di-tert-butylhydroquinone,
Examples thereof include di-tert-butyl-p-cresol, hydroquinone monomethyl ether, and 2,6-di-tert-butyl-4-methylphenol. The polymerization inhibitor is preferably used in an amount of 0.5% by weight or less based on the total amount of the unsaturated polyester resin and the polymerizable monomer. When a curing agent is blended, it is preferable to contain 0.05% by weight or more for storage stability.

Examples of the filler include calcium carbonate, magnesium carbonate, barium carbonate, barium sulfate, calcium sulfate, aluminum hydroxide, silica, clay, talc, silica sand, diatomaceous earth, mica powder, glass powder, glass balloon and the like. Organic fillers such as inorganic fillers, wood powder, polyethylene powder, and pulverized products of various FRP molded products. The amount of the filler used is determined in consideration of the physical properties such as the strength of the molded article, the viscosity of the unsaturated polyester resin composition, and the fluidity, but is based on the total amount of the unsaturated polyester resin and the polymerizable monomer. Preferably it is 100 to 200% by weight, especially 105 to 150% by weight.
It is preferable that If the amount of the filler is too small, sedimentation may occur, and if the amount of the filler is too large, the viscosity tends to be high and stirring tends to be difficult. It is preferable to use 60 to 100% by weight of heavy calcium carbonate having a representative particle diameter of 0.08 to 1.0 μm among the fillers. If the amount of the heavy calcium carbonate is too small, the effect of the present invention is reduced.

As the thickener, for example, magnesium oxide, magnesium hydroxide, calcium oxide, potassium oxide, potassium hydroxide, zinc oxide and the like are used. The amount of the thickener is determined according to the workability of molding. The thickener is preferably 0.5 to 5% by weight, more preferably 0.7 to 2% by weight, based on the total amount of the unsaturated polyester resin and the polymerizable monomer. If the amount of the thickener is too small, the viscosity of the resin composition may not increase. On the other hand, if there is too much thickener, the viscosity may be too high to control.

As the internal release agent, an aliphatic organic acid such as stearic acid, a metal salt thereof, a wax-based compound, a silicone-based compound or the like can be used alone or in combination of two or more. The amount of the internal release agent is preferably 1 to 10% by weight, more preferably 2 to 4% by weight, based on the total amount of the unsaturated polyester resin and the polymerizable monomer. If the amount of the release agent is too small, the molded product may stick to the mold, making it difficult to remove the molded product, and may cause cracks or the like in the molded product. Also,
If the release agent is too large, the molded article strength tends to decrease.

The reinforcing fibers used in the present invention include glass fibers, carbon fibers, whiskers, organic synthetic fibers, and natural fibers. In the present invention, glass fibers are preferred.
These reinforcing fibers are used in the form of continuous fibers, woven fabrics, non-woven fabrics, and the like, and those obtained by cutting a roving-shaped material into appropriate lengths, for example, those cut into 20 to 30 mm are preferably used. The amount of the reinforcing fiber used depends on the required strength, but is preferably in the range of 15 to 35% by weight based on the total amount of the unsaturated polyester resin and the polymerizable monomer.

Next, a method for producing the sheet-shaped molding material of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory diagram of a method for producing a sheet-shaped molding material of the present invention. The paste-like resin composition 4 produced by blending the various components as described above is applied on the release film 1 so as to have a uniform thickness, and is cut to a predetermined length by the cutter 3. And the paste-like resin composition 4 is discharged from the paste discharge nozzle 6 under pressure, and then uniformized by the blade 5, and then the reinforcing fiber 2 is cut again. Cut with 3 and spray. afterwards,
Another film 1 coated with the paste-like resin composition 4 is
The scattered reinforcing fibers 2 are overlapped with each other so as to be sandwiched by the paste-like resin composition, wound up on a roll, and aged, if necessary, to obtain a sheet-like molding material. When a thickener is blended, it is preferable to heat to a temperature of from room temperature to 60 ° C. for aging. As a result, a sheet-shaped molding material in which the resin layer, the reinforcing fiber layer, the resin layer, the reinforcing fiber layer, the resin layer, and the release film are sequentially laminated on the release film is obtained.

[0023]

Next, the present invention will be described more specifically with reference to examples, but the present invention is not limited thereto.

Example 1 [Synthesis of unsaturated polyester resin] Terephthalic acid 996
Parts by weight, 506 parts by weight of propylene glycol, 312 parts by weight of neopentyl glycol and ethylene glycol 3
72 parts by weight were charged into a 3 liter flask equipped with a thermometer, a nitrogen blowing tube, a rectification tower and a stirrer, and heated with a mantle heater to elevate the temperature to 230 ° C. in 5 hours. Thereafter, the mixture was cooled to 220 ° C., kept warm and cooled when the acid value became 12, 882 parts by weight of maleic anhydride was added, and the temperature was raised again to 215 ° C. in 5 hours. Then 210
When the acid value reached 18 by cooling to 18 ° C., the reaction was terminated.

[Preparation of unsaturated polyester resin composition]
620 parts by weight of the unsaturated polyester resin obtained above was dissolved in 380 parts by weight of styrene as a polymerizable monomer, and then 0.02 parts by weight of hydroquinone was dissolved as a polymerization inhibitor. 2 of the obtained unsaturated polyester resin composition
The viscosity at 5 ° C. was 1.54 Pa · s, and the hue was 1 or less in Gardner number.

A paste-like resin composition comprising the components shown in Table 1 was prepared.

[Table 1]

In this embodiment, the glass fibers (R
The content of ES450PE-750AS (trade name, manufactured by Nitto Boseki Co., Ltd.) was 25% by weight based on the unsaturated polyester resin composition.

Using the obtained paste-like resin composition,
A sheet-shaped molding material was produced using the equipment shown in FIG. 1 under the following conditions. Coating speed: 2.0 m / min Doctor blade gap: 0.8 mm The thickness of the sheet-like molding material thus obtained was 3.2 mm. Using the sheet-like molding material, a mold temperature of 145 is used.
The molded product obtained under the conditions of ° C / 130 ° C, thickness of 5 mm, dwelling time of 6 minutes and pressure of 7 MPa did not generate any swelling or other defects even when immersed in 96 ° C hot water for 100 hours. . Further, when the cross section of the sheet-shaped molding material was observed, the glass fiber was favorably impregnated with the paste-like resin composition.

Comparative Example A paste-like resin composition having the same composition as in Example 1 was used.
Only the base, without the paste discharge nozzle and the blade) to obtain a sheet-like molding material. Coating speed: 2.0 m / min Doctor blade gap: 1.2 mm The thickness of the obtained sheet-like molding material was 3.1 mm.
This was molded in the same manner as in the example, and 100
When immersed for a time, blisters occurred. When the cross section of the sheet-shaped molding material was observed, there was a glass fiber layer not impregnated with the paste-like resin composition, and this portion was avoided.

[0030]

According to the method for producing a sheet-like molding material of the present invention, a sheet-like molding material having a thickness of about 1.5 to 3 times is obtained at the same coating speed as the conventional production method, and the productivity is improved. I do. In addition, the amount of film used, the amount of film discarded, and the work of cutting out the sheet-shaped molding material during the molding operation can be reduced.
Furthermore, the thickness of the sheet-like molding material is set to 3 to 4 mm while ensuring the impregnation of the paste-like resin composition into the glass fibers.
And a molded article having excellent quality can be obtained.

[Brief description of the drawings]

FIG. 1 is an illustration of a method for producing a sheet-like molding material of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Release film 2 Reinforcement fiber 3 Cutter 4 Paste resin composition 5 Blade 6 Paste discharge nozzle

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) // B32B 27/36 101 B32B 27/36 101 B29K 33:04 F term (reference) 4F071 AA49 AB03 AB28 AC02 AC10 AD01 AE17 AE22 AH19 CA03 CB01 CC06 CD05 4F100 AK44A AK44C AK44E BA05 BA07 BA08 BA10A BA10E DG01B DG01D DH02 EH462 EH762 EJ91 JL00 JL02 4F205 AA41 AB25 AD16 AG03 AM32 HA14 HA29 HA33 HA36 HA37 HA04 H04 HF24 HF04 HF04 HF04 HT20 HT23 HT24 4J002 CF221 DA017 DL007 EA046 EH076 EP016 FA047 FA067 FD017

Claims (1)

[Claims] 1. A paste-like resin composition containing an unsaturated polyester resin and a polymerizable monomer is applied on a release film, a reinforcing fiber is sprayed thereon, and the paste-like resin composition is further applied thereon. A method for producing a sheet-shaped molding material, comprising: placing a resin composition, uniformly applying the resin composition with a blade, and then scattering a reinforcing fiber and a release film coated with the paste-like resin composition. .