JP2006037267A - Chopped strand and fiber-reinforced polyacetal resin molding material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a chopped strand providing strong reinforcing effects to a polyacetal resin; and to provide a fiber-reinforced polyacetal resin molding material. <P>SOLUTION: The chopped strand providing the high reinforcing effects to the polyacetal resin is obtained by using a sizing agent containing a polyacrylic acid, an ammonium halide, a polyurethane resin and an aminosilane-based coupling agent, and attaching the sizing agent so that the proportion of the sizing agent expressed in terms of solid may be 0.1-1.0 mass% based on the whole amount of the chopped strand. The fiber-reinforced polyacetal resin molding material obtained by using the chopped strand as a reinforcing material can provides a polyacetal resin molded product having excellent mechanical strength. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a chopped strand and a fiber reinforced polyacetal resin molding material for obtaining a polyacetal resin molded article having excellent mechanical strength.

  Polyacetal resins are excellent in mechanical strength, electrical properties, and chemical properties, and are used in various fields such as electronics, automobiles, OA equipment, machinery, and home appliances.

  In general, a resin molded product made of a thermosetting resin and a thermoplastic resin uses chopped strands such as glass fiber as a reinforcing material, and improves the mechanical strength by kneading the reinforcing material with the resin. . However, since the polyacetal resin is chemically inert, a remarkable reinforcing effect can be obtained even when a reinforcing material such as glass fiber is blended, compared to polyamide resin, polycarbonate resin, polyethylene terephthalate resin, and the like. There is a problem that it is difficult.

  In order to solve the above problem, for example, in Patent Document 1, a glass fiber bundle provided with a bundling agent containing a urethane resin mainly composed of xylylene diisocyanate, a silane coupling agent, a cationic lubricant, and phosphorous acid. The mechanical strength of the polyacetal resin molding material is improved by using the glass fiber bundle as a reinforcing material.

Patent Document 2 below discloses a glass fiber sizing agent containing a tetrafunctional epoxy resin emulsion, a silane coupling agent, a cationic lubricant, and acetic acid. The mechanical strength of the polyacetal resin molding material is improved by using a glass fiber bundle as a reinforcing material.
JP 2000-335842 A Japanese Unexamined Patent Publication No. 60-221343

  In Patent Document 1, acetic acid is used as the sizing agent in order to make the cationic lubricant contained in the sizing agent water-soluble and homogeneous. Therefore, when the sizing agent is applied to the glass fiber, acetic acid may remain on the surface of the glass fiber. This remaining acetic acid decomposes the polyacetal resin, which hinders improvement of the mechanical strength of the polyacetal resin molding material.

  Moreover, in the said patent document 2, in order to improve the mechanical strength of a polyacetal resin molded article by suppressing decomposition | disassembly of a polyacetal resin, in order to make a cationic lubricant water-soluble and to make a homogeneous sizing agent, pH adjuster As phosphorous acid is used. However, since the polyacetal resin itself is chemically inert, the adhesion between the polyacetal resin and the glass fiber is not good, and sufficient mechanical strength cannot be obtained.

  Therefore, the present invention has been made in view of the above problems, and an object thereof is to provide a chopped strand and a fiber reinforced polyacetal resin molding material capable of improving the mechanical strength of a polyacetal resin molding.

  Since the polyacetal resin itself is chemically inert, the present inventors tend to have poor adhesion between the glass fiber and the polyacetal resin when the polyacetal resin is reinforced with glass fiber, which affects the reinforcing effect of the polyacetal resin. I thought.

  Then, paying attention to improving the adhesiveness between the polyacetal resin and the glass fiber, as a result of earnestly examining the component that appropriately decomposes and activates the polyacetal resin among the components contained in the sizing agent, the present invention has been achieved. .

  That is, the chopped strand of the present invention contains polyacrylic acid, ammonium halide, polyurethane resin, and aminosilane coupling agent as a sizing agent, and the solid content of the sizing agent is 0.1% relative to the total amount of chopped strands. It is characterized by adhering to -1.0 mass%.

  The chopped strand using the sizing agent appropriately decomposes the polyacetal resin, and the decomposed product reacts again with the sizing agent applied to the chopped strand, so that the interfacial adhesion between the chopped strand and the polyacetal resin is extremely high. It can be good. Therefore, the chopped strand of the present invention has a very high reinforcing effect of the polyacetal resin.

  The sizing agent of the present invention has a solid content of ammonium halide of 0.3 to 3 parts by mass, a solid content of polyurethane resin of 10 to 100 parts by mass, and an aminosilane with respect to 100 parts by mass of the solid content of polyacrylic acid. The solid content of the system coupling agent is preferably 5 to 50 parts by mass.

  The sizing agent of the present invention preferably contains a fluorescent brightening agent. According to this, yellowing of the chopped strand can be prevented and the color tone can be improved.

  And it is preferable that the fluorescent whitening agent contained in the sizing agent of this invention is 0.3-3 mass parts with respect to 100 mass parts of solid content of polyacrylic acid.

  The polyurethane resin used for the sizing agent of the present invention is preferably composed of an isocyanate component mainly composed of xylylene diisocyanate and a polyol component mainly composed of poly (ε-caprolactone) diol. .

  Furthermore, in the present invention, it is preferable to use ammonium bromide as the ammonium halide.

  On the other hand, the fiber reinforced polyacetal resin molding material of the present invention is characterized in that the chopped strand prepared as described above is contained in the polyacetal resin in an amount of 5 to 70% by mass.

  The fiber reinforced polyacetal resin molding material using the chopped strands of the present invention can provide a polyacetal resin molded article having excellent mechanical strength. Moreover, if the glass content is within the above range, both cost and mechanical strength can be achieved.

  The chopped strand for a fiber-reinforced polyacetal resin molding material of the present invention has a solid content of a sizing agent containing polyacrylic acid, ammonium halide, polyurethane resin, and aminosilane coupling agent in an amount of 0. 0 relative to the total amount of the chopped strand. 1-1.0 mass% adheres and can provide a high reinforcement effect especially with respect to polyacetal resin.

  And the fiber reinforced polyacetal resin molding material using the chopped strand of this invention can provide the polyacetal resin molded product excellent in mechanical strength.

  The chopping strand bundling agent in the present invention contains polyacrylic acid, ammonium halide, polyurethane resin, and aminosilane coupling agent.

  The polyacrylic acid used in the sizing agent of the present invention is preferably a polymer of acrylic acid, a copolymer of acrylic acid and one or more monomers, or a mixture thereof.

  Polyacrylic acid moderately decomposes polyacetal resin, but it is speculated that this decomposed product and polyacrylic acid react further, and the interfacial adhesion between chopped strand bundling agent and polyacetal resin is improved. High reinforcing effect can be expected.

  And as a monomer used for manufacture of the copolymer with the above-mentioned acrylic acid, for example, ethylene, propylene, isobutylene, styrene, α-methylstyrene, vinyl acetate, butadiene, isoprene, chloroprene, acrylic acid ester, Methacrylic acid esters and the like are preferably used. Two or more of these monomers may be used in combination.

  The ammonium halide used in the sizing agent of the present invention improves the mechanical strength of the fiber-reinforced polyacetal resin molding material, and preferred specific examples include ammonium chloride and ammonium bromide. More preferred. The said ammonium halide has a function which decomposes | disassembles a polyacetal resin moderately, By using together with polyacrylic acid, the mechanical strength of a fiber reinforced polyacetal resin molding material can be improved synergistically.

  And as for the ammonium halide contained in a sizing agent, it is preferable that solid content of ammonium halide is 0.3-3 mass parts with respect to 100 mass parts of solid content of polyacrylic acid, 0.5-2 More preferably, it is part by mass. When the solid content of the ammonium halide contained in the sizing agent is less than 0.3 parts by mass, when the chopped strand is used as a reinforcing material for the polyacetal resin, a sufficient reinforcing effect cannot be obtained. When it exceeds, when the molded product obtained as a result is heat-processed, since gas generation amount increases, it is unpreferable.

  As the aminosilane coupling agent used in the sizing agent of the present invention, an aminosilane coupling agent conventionally used for surface treatment of glass fibers can be used, preferably a monoaminosilane or diaminosilane, particularly from the viewpoint of color tone, Monoaminosilane is more preferred.

  Preferable specific examples include γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -N′-β- (aminoethyl)- Examples include γ-aminopropyltriethoxysilane, γ-anilinopropyltrimethoxysilane, and the like. Two or more of these coupling agents may be used in combination.

  And as for content of the aminosilane type coupling agent contained in a sizing agent, it is preferable that solid content of an aminosilane type coupling agent is 5-50 mass parts with respect to 100 mass parts of solid content of polyacrylic acid, and more. Preferably, the solid content is 10 to 30 parts by mass. When the solid content of the aminosilane coupling agent contained in the sizing agent is less than 5 parts by mass, a sufficient reinforcing effect cannot be obtained when the chopped strand is used as a reinforcing material for the polyacetal resin, and 50 parts by mass. If it is larger, the color tone of the chopped strand is yellowed, which is not preferable.

  The polyurethane resin used in the sizing agent of the present invention improves the sizing property of chopped strands, and is a conventionally known one formed from a polymer polyol, an organic diisocyanate, and optionally a chain extender and / or a crosslinking agent. Can be preferably used and is preferably used in the form of an aqueous dispersion such as an emulsion or a dispersion.

  Preferred examples of the polymer polyol include, for example, i) polyethylene adipate diol, polybutylene adipate diol, polyethylene butylene adipate diol, polyneopentyl adipate diol, polyneopentyl terephthalate diol, poly (ε-caprolactone) diol, poly Polyester polyols such as valerolactone diol and polyhexamethylene carbonate diol, ii) Polyethers such as polyethylene glycol, polypropylene glycol, polyoxyethyleneoxypropylene glycol, polyoxytetramethylene glycol, ethylene oxide and / or propylene oxide adducts of bisphenols A polyol is mentioned.

  Specific examples of preferred organic diisocyanates include i) 2,4′- or 4,4′-diphenylmethane diisocyanate (MDI), 2,4- or 2,6-tolylene diisocyanate (TDI), 4, 4'-dibenzyl diisocyanate, 1.3- or 1,4-phenylene diisocyanate, 1,5-naphthylene diisocyanate, aromatic diisocyanate such as xylylene diisocyanate (XDI), ii) ethylene diisocyanate, hexamethylene diisocyanate (HDI) Alicyclic diisocyanates such as lysine diisocyanate, iii) isophorone diisocyanate (IPDI), 4,4′-dicyclohexylmethane diisocyanate, etc., and two or more of these may be used in combination. .

  As the chain extender and / or the crosslinking agent, an active hydrogen-containing compound having a number average molecular weight of 60 to 500 is preferable. For example, i) ethylene glycol, propylene glycol, 1,3-butylene glycol, 1,4-butanediol, 1 , 6-hexanediol, 3-methylpentanediol, diethylene glycol, neopentyl glycol, 1,4-bis (hydroxymethyl) cyclohexane, 1,4-bis (hydroxyethyl) benzene, 2,2-bis (4,4 ' Dihydroxy alcohols such as -hydroxycyclohexyl) propane, trihydric alcohols such as glycerin and trimethylolpropane, pentaerythritol, diglycerin, α-methylglucoside, sorbitol, xylit, mannitol, dipentaerythris Retort, glucose, fructose, shi Polyhydric alcohols such as 4- to 8-valent alcohols such as sucrose, ii) polyhydric phenols such as pyrogallol, catechol, hydroquinone, iii) bisphenol A, bisphenol F, bisphenol S, etc. Iv) Aliphatic polyamines such as ethylenediamine, hexamethylenediamine and diethylenetriamine, v) Isophoronediamine, alicyclic polyamines such as 4,4'-dicyclohexylmethanediamine, vi) 4,4'- And aromatic polyamines such as diaminodiphenylmethane, vii) aromatic alicyclic polyamines such as xylylenediamine, and viii) polyamines such as hydrazine or derivatives thereof.

  In the present invention, the polyol component of the polyurethane resin is preferably a poly (ε-caprolactone) diol among the above-mentioned polymer polyols, and the isocyanate component is preferably an organic diisocyanate listed above. XDI is preferably used. A chopped strand using a polyurethane resin composed of polycaprolactone diol and XDI is more preferable because of its extremely high convergence.

  And as for the polyurethane resin contained in a sizing agent, it is preferable that solid content of a polyurethane resin is 10-100 mass parts with respect to 100 mass parts of polyacrylic acid solid content, More preferably, it is 20-80 mass parts. is there. If the solid content of the polyurethane resin is less than 10 parts by mass, the chopped strands will not have sufficient converging properties. If the solid content exceeds 100 parts by mass, the converging property will not be improved so much and the reinforcing effect of the polyacetal resin will be reduced. Therefore, it is not preferable.

  It is preferable to add a fluorescent brightening agent to the sizing agent of the present invention, whereby yellowing of the chopped strand and the fiber reinforced polyacetal resin molding material can be prevented and the color tone can be adjusted.

  Examples of the optical brightener that can be used in the present invention include benzoxazole, triazole, coumarin, pyrazoline, styryl, and naphthalimide, and benzoxazole or triazole is particularly preferable.

  And as for content of a fluorescent whitening agent, it is preferable that solid content of a fluorescent whitening agent is 0.3-3 mass parts with respect to 100 mass parts of solid content of polyacrylic acid. When the solid content of the optical brightener is less than 0.3 parts by mass, the color tone improving effect of the chopped strand and the fiber reinforced polyacetal resin molding material cannot be sufficiently obtained. On the other hand, if it exceeds 3 parts by mass, it is not preferable because it is not preferable economically and is bluish.

  In addition to the above components, the sizing agent of the present invention may further contain a surfactant, a lubricant, and an antistatic agent.

  As the surfactant, nonionic surfactants are preferable, and examples thereof include ethylene oxide propylene oxide copolymers, synthetic alcohols, natural alcohols, fatty acid esters, and distyrenated phenols.

  As the lubricant, fatty acid amides, quaternary ammonium salts and the like can be contained. Examples of fatty acid amides that can be used include dehydration condensates of polyethylene polyamines such as diethylenetriamine, triethylenetetramine, and tetraethylenepentamine with fatty acids such as lauric acid, myristic acid, palmitic acid, and stearic acid. Moreover, as a quaternary ammonium salt, lauryl trimethyl ammonium chloride, an alkyl trimethyl ammonium salt, etc. can be used together.

  As the antistatic agent, inorganic salts such as lithium chloride and potassium iodide, and quaternary ammonium salts such as ammonium chloride type and ammonium ethosulphate type can be preferably used.

  The sizing agent used in the present invention includes the polyacrylic acid, ammonium halide, aminosilane coupling agent and polyurethane resin, and, if necessary, an optical brightener, a surfactant, a lubricant, an antistatic agent and the like. The agent can be readily prepared, for example, by mixing in an aqueous medium.

  And it is preferable to give a sizing agent so that solid content may be 0.1-1.0 mass% with respect to a total of 100 mass parts of glass fiber and a sizing agent, 0.2-0.5 mass% It is more preferable to give so that it may become. When the applied amount is less than 0.1% by mass, the converging property is inferior, and the reinforcing effect of the polyacetal resin cannot be obtained so much. When the applied amount exceeds 1.0% by mass, gas generation during heating increases, which is not preferable. .

  In the present invention, the method for producing chopped land is not particularly limited, and various conventionally known methods can be used.

  For example, molten glass is drawn out from a number of nozzles attached to the bottom of the bushing, and a sizing agent is applied to the glass fiber with an applicator or spray, and the glass fiber bundle is preferably cut into 1.5 to 13 mm. At that time, the glass fiber bundle may be wound once and then cut, or may be cut as it is without being wound.

  Next, the process proceeds to the drying process of the cut glass fiber bundle, but the sizing agent may be applied again before the drying process. The drying temperature and the drying time are arbitrary and not particularly limited. In order to efficiently perform the drying process without impairing the converging property of the glass fiber bundle, the drying temperature is 120 to 220 ° C., and the drying time is 10 seconds to 10 minutes. It is preferable that

  The chopped strand of this invention is obtained as mentioned above.

  Moreover, a fiber-reinforced polyacetal resin molding material is obtained by impregnating the chopped strand with a melted polyacetal resin.

  In the present invention, the polyacetal resin is not particularly limited. For example, a modified polyacetal resin such as a polyoxymethylene homopolymer, a formaldehyde-ethylene oxide copolymer obtained from trioxane and ethylene oxide, a polyurethane-containing polyacetal, or an elastomer-containing polyacetal Is mentioned.

  In the present invention, the method for producing the fiber-reinforced polyacetal resin molding material is not particularly limited, and various conventionally known methods can be used.

  For example, while the polyacetal resin melted from the screw extruder is plasticized, the chopped strand is supplied thereto and melt-kneaded. The melt-kneaded product is molded into a linear fiber-reinforced polyacetal resin body, and then cut with a pelletizer or the like to obtain a fiber-reinforced polyacetal resin molding material. Moreover, the fiber reinforced polyacetal resin molding material can also be obtained by a known method using an injection molding machine.

  And the glass content rate of a fiber reinforced polyacetal resin molding material has preferable 5-70 mass%, More preferably, it is 10-60 mass%. If the glass content of the fiber-reinforced polyacetal resin molding material is less than 5% by mass, the mechanical strength is poor and unsuitable for practical use, and if it exceeds 70% by mass, the production cost increases.

  Hereinafter, the present invention will be specifically described with reference to examples. However, these examples are illustrative of embodiments of the present invention and are not intended to limit the scope of the present invention.

[Production of chopped strands]
3,000 glass fibers having an average diameter of 10 μm are converged, the raw materials shown in Table 1 are used, and the sizing agent of Production Examples 1 to 11 adjusted at the blending ratio (parts by mass) shown in Table 2 is applied and cut to 3 mm. Thus, chopped strands of Examples 1 to 8 and Comparative Examples 1 to 3 were obtained.

[Production of polyacetal resin molded product]
To the polyacetal copolymer (MFR45), the chopped strands of Examples 1 to 8 and Comparative Examples 1 to 3 were added, and a fiber reinforced with a glass content of 25% by mass at a molding temperature of 220 ° C. using a twin screw extruder with a screw diameter of 35 mm. A polyacetal resin molding material was obtained.

  Next, molding was performed at a clamping load of 75 t, a cylinder temperature of 190 to 210 ° C., and a mold of 80 ° C. to obtain a pellet-shaped polyacetal resin molded product.

[Performance evaluation of chopped strands and polyacetal resin molded products]
<Fuzz amount measurement>
3 kg of chopped strands are put into a V mixer having a capacity of 10 liters with a middle blade installed therein, and stirred for 15 minutes at a mixer rotation speed of 30 rpm and a middle blade rotation speed of 480 rpm (the direction opposite to the rotation of the mixer). Thereafter, the mixture was sieved with a sieve having an opening of 3.35 mm, the fluff remaining on the sieve was collected, and the fluff weight was precisely weighed. If the fluff weight was 10 g or less, it was judged that the chopped strands had good convergence.

<Tensile strength measurement>
It was measured by a method based on ASTM D-638 and judged to be good if it was 130 MPa or more.

<Measurement of bending strength>
It was measured by a method based on ASTM D-790 and judged to be good if it was 190 MPa or more.

<IZOD impact strength measurement>
It measured with the method based on ASTM D-256 with a 1/8 inch notch, and judged that it was favorable if it was 6.5 MPa or more.

<Color tone>
Using a color difference meter (Σ-90, manufactured by Nippon Denshoku Co., Ltd.), the color tone of the resin molding material in the form of pellets was measured. If the b value is in the range of 1 to 5, the color tone is almost the same as the color tone possessed by the polyacetal resin, so the color tone was judged to be good.

<Heat loss rate>
The polyacetal resin molded product adjusted to 1.5 g was baked at 230 ° C. for 60 minutes, and the thermal weight loss rate was determined. If the heat loss rate was 1.5% or less, it was determined that the amount of gas generated could be sufficiently suppressed.

  The above items were evaluated for the chopped strands of Examples 1 to 8 and Comparative Examples 1 to 3 and the polyacetal resin molded product, and the results are shown in Table 3.

  From the above results, the polyacetal resin molded product of Comparative Example 1 in which ammonium halide is not used as a sizing agent and Comparative Example 3 in which ammonium halide and polyacrylic acid are not used are inferior in mechanical strength. The chopped strand of Comparative Example 2 in which no resin was used had poor convergence.

  On the other hand, the chopped strands of Examples 1 to 8 using the sizing agent containing polyacrylic acid, ammonium halide, urethane resin, and aminosilane coupling agent are excellent in sizing property, and polyacetal resin using the chopped strand The molded product is excellent in mechanical strength.

  In addition, the polyacetal resin molded products of Examples 1 to 6 using a sizing agent that further contains 0.3 to 3% by mass of a fluorescent brightener in terms of solid content can suppress yellowing and bluishness. The color tone can be almost the same as that of the polyacetal resin.

  And the polyacetal resin molded product of Examples 1-5 whose content of a polyurethane resin is 10-100 mass parts is more excellent in mechanical strength, Furthermore, solid content of ammonium halide is 0.3-3. The polyacetal resin molded products of Examples 1 to 4 which are parts by mass can reduce the amount of gas generated by heating.

  Therefore, according to the present invention, it is possible to obtain a chopped strand that is excellent in color tone and convergence and has a small amount of gas generated by heating, and a fiber-reinforced polyacetal resin molding material using the chopped strand as a reinforcing material is a machine A polyacetal resin molded product having good strength and color tone can be provided.

The chopped strand of the present invention has a high effect of reinforcing the polyacetal resin, and the fiber-reinforced polyacetal resin molding material using the chopped strand can provide a polyacetal resin molded product having excellent mechanical strength.

Claims (7)

  As a sizing agent, polyacrylic acid, ammonium halide, polyurethane resin, and aminosilane coupling agent are included, and the solid content of the sizing agent is 0.1 to 1.0% by mass based on the total amount of chopped strands. Chopped strand characterized by   The sizing agent has a solid content of ammonium halide of 0.3 to 3 parts by mass, a solid content of polyurethane resin of 10 to 100 parts by mass, and an aminosilane coupling agent with respect to 100 parts by mass of polyacrylic acid. The chopped strand according to claim 1, wherein the solid content is 5 to 50 parts by mass.   The chopped strand according to claim 1 or 2, further comprising a fluorescent brightener as a component of the sizing agent.   4. The chopped strand according to claim 1, wherein the fluorescent brightener contained in the sizing agent is 0.3 to 3 parts by mass with respect to 100 parts by mass of the solid content of polyacrylic acid.   The said polyurethane resin is comprised by the isocyanate component which has a xylylene diisocyanate as a main component, and the polyol component which has a poly ((epsilon) -caprolactone) diol as a main component. Chopped strand.   The chopped strand according to any one of claims 1 to 5, wherein the ammonium halide is ammonium bromide. A fiber-reinforced polyacetal resin molding material having a glass content of 5 to 70% by mass obtained by kneading the chopped strand according to any one of claims 1 to 6 and a polyacetal resin.