JPH0525260B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to insert molded products. Specifically, it relates to an insert molded product with improved high and low temperature impact properties. [Prior art] Insert molding is a molding method in which metals, etc. are embedded in resin, taking advantage of the characteristics of resin and the characteristics of metals or inorganic solid materials (hereinafter referred to as metals, etc.). It has been applied to a wide range of fields such as electronic parts and OA equipment parts, and is now one of the most common molding methods. However, resins and metals have extremely different expansion and contraction rates (so-called linear expansion coefficients) due to temperature changes, so molded products with thin resin parts or parts with large thickness changes, and gates If the position is not appropriate and the product sag, there are many problems such as cracking immediately after molding or cracking due to temperature changes during use. For this reason, the current situation is that the applications and shapes of molded products are quite limited. Recently, in the automobile field, the use of resin for engine parts has progressed, and insert molded products are also becoming important parts. Particularly for parts of ignition systems and distributors, an insert molding method is being considered in which metal parts such as aluminum, copper, iron, and steel are wrapped in polybutylene terephthalate resin. In addition to the complicated structure and the fact that there are many parts where the resin wall thickness changes, the location where it is used is near the engine causes large temperature changes. Therefore, for these reasons, there has recently been a strong demand for resins that can withstand long-term changes in high and low temperatures, that is, resins that have excellent high and low temperature impact resistance. [Object of the Invention] Based on the above, the present inventors have completed the present invention by intensively studying the possibility of obtaining a polybutylene terephthalate resin composition having excellent high and low temperature impact properties. That is, the purpose of the present invention is to provide a polybutylene terephthalate resin composition that is industrially valuable and suitable for insert molding. 1 to 50 parts by weight of an acrylic rubber obtained by graft polymerizing a graft polymerizable monomer to a polymer obtained by polymerizing an acrylic acid ester and a small amount of a crosslinking monomer, and a metal or inorganic solid. An insert molded product having excellent high and low temperature impact resistance is obtained by insert molding a product. [Structure of the Invention] The polybutylene terephthalate resin used in the present invention is mainly a polyester containing butylene glycol as a glycol component and terephthalic acid as a dicarboxylic acid, but a small amount of this component can be used as other raw materials, such as a glycol component. Fatty acid diols such as ethylene glycol, propylene glycol, hexamethylene glycol, and decamethylene glycol, aromatic diols such as alkylene glycol adducts of bisphenol A or their halides, and dicarboxylic acid components such as phthalic acid and isophthalic acid. Acid, aromatic carboxylic acid such as hexahydrophthalic acid and naphthalene dicarboxylic acid, aliphatic carboxylic acid such as adipic acid, sebacic acid and azelaic acid, etc. may be substituted. The acrylic rubber used in the present invention is a rubber-like elastic material obtained by polymerization of acrylic ester or copolymerization mainly composed of acrylic ester, and typically contains an acrylic ester such as butyl acrylate and a small amount of acrylic ester. Examples include rubber-like polymers obtained by graft polymerizing a graft polymerizable monomer such as methyl methacrylate to a polymer obtained by polymerizing a crosslinkable monomer such as butylene diacrylate. Examples of the acrylic esters include butyl acrylate, methyl acrylate, ethyl acrylate, propyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, and the like. In addition to butylene diacrylate, examples of crosslinking monomers include butylene dimethacrylate, polyols such as trimethylolpropane trimethacrylate, and esters of acrylic acid or methacrylic acid, divinylbenzene, vinyl acrylate, vinyl methacrylate, etc. The compounds include allyl compounds such as allyl acrylate, allyl methacrylate, diallyl maleate, diallyl fumarate, diallyl itaconate, monoallyl maleate, monoallyl fumarate, and triallyl cyanurate. In addition, as the above graft polymerizable monomer,
In addition to methyl methacrylate, examples include methacrylic acid esters such as ethyl methacrylate, butyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, styrene, acrylonitrile, and the like. A part of this graft polymerizable monomer can also be copolymerized by using it when producing a polymer by polymerizing the above-mentioned acrylic ester and a crosslinking monomer. The above-mentioned acrylic rubbers include, for example, Kane Ace FM manufactured by Kanebuchi Chemical Co., Ltd., Vitax V-6401 manufactured by Hitachi Chemical Co., Ltd., Metablane W-300 and Mitsubishi Rayon Co., Ltd. W-530, It is also commercially available as Acryloid KM-323, Acryloid KM-330 (trademarks), etc. manufactured by Rohm and Haas. The ratio of polybutylene terephthalate to acrylic rubber is 99:1 to 50:50 parts by weight, preferably 97:
3 to 70:30, more preferably 95:5 to 80:20 parts by weight. If the amount of acrylic rubber is too small, a composition with excellent high and low temperature impact properties cannot be obtained. On the other hand, if the amount is too large, the properties of the resin will be lost and the mechanical properties of the molded product itself will be deteriorated, which is not preferable. In the present invention, more excellent effects can be obtained by adding an epoxy compound and a pentaerythritol ester, and further a carbodiimide compound together with the epoxy compound and pentaerythritol ester, in addition to the above-mentioned acrylic rubber. The epoxy compounds used in the present invention include:
Aliphatic epoxy compounds such as allyl glycidyl ether, bisepoxy dicyclopentadienyl ether of ethylene glycol, epoxidized soybean oil, epoxidized linseed oil, butadiene diepoxide, octyl epoxytalate, epoxidized polybutadiene, bisphenol A di Aromatic epoxy compounds such as glycidyl ether, tetraphenyl ethylene epoxide, diglycidyl ester of phthalic acid, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 3,4-epoxy-6-methylcyclohexyl Methyl-3,4-epoxy-6
-methylcyclohexanecarboxylate, 2,
3-Epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 4-
(3,4-epoxy-5-methylcyclohexyl)
Butyl-3,4-epoxycyclohexanecarboxylate, 3,4-epoxycyclohexylethylene oxide, cyclohexylmethyl-3,
4-epoxycyclohexane carboxylate,
3,4-epoxy-6-methylcyclohexylmethyl-6-methylcyclohexanecarboxylate, vinylcyclohexene oxide, bis(3,
4-Epoxycyclohexylmethyl)adipate, bis(3,4-epoxy-6-methylcyclohexylmethyl)adipate, 2-(3,4-epoxycyclohexyl-5,5-spiro-3,4
-epoxy) cyclohexane-metadioxane and other alicyclic epoxy compounds. The amount added is 0.01 to 5% based on the total amount of polybutylene terephthalate resin and acrylic rubber.
% by weight, preferably 0.02-2% by weight. If it is too small, the expected effect will not be achieved. On the other hand, if there is too much, coloring etc. will occur. In addition, the pentaerythritol ester has the general formula [] [RS(-CH ₂ )- _n COOCH ₂ ] _o C(CH ₂ OH) _4-o ...[] (wherein, R is an alkyl group having 5 to 30 carbon atoms. , n is 1
The number ˜4, m indicates the number 1-3. ), and the alkyl group represented by R is a pentyl group, hexyl group, octyl group, 2-ethylhexyl group, nonyl group, decyl group, dodecyl group, tetradecyl group, hexadecyl group, octadecyl group,
Examples include eicosyl groups and the like. If the number of carbon atoms in the alkyl group represented by R is too small, it will easily sublime during molding of the polyester resin composition, resulting in the inconvenience of contaminating the molded product and molding machine. Conversely, if the number of carbon atoms in the alkyl group is too large, the effect of preventing coloring due to heat will be reduced. Preferred alkyl groups have about 8 to 20 carbon atoms. Although n is a number from 1 to 4, a number from 3 to 4 is preferred, particularly a number from 4 because of the effect of preventing coloring due to heat. Moreover, m is preferably 2. Specific examples of pentaerythritol esters represented by the above general formula [] include pentaerythritol tetrakis (dodecylthiopropionate), pentaerythritol tetrakis (dodecylthioacetate), pentaerythritol tetrakis (dodecylthiobutyrate), and pentaerythritol tetrakis (dodecylthiobutyrate). Examples include tetrakis (octadecylthiopropionate), pentaerythritol tetrakis (2-ethylhexylthiopropionate), pentaerythritol tris (dodecylthiopropionate), pentaerythritol bis(dodecylthiopropionate), and the like. Among these pentaerythritol tetrakis (dodecylthiopropionate) is a trademark from Mitsubishi Yuka Co., Ltd.
It is also commercially available as Senox 412S, and is one of the preferred products. The amount added is 0.01 to 5% by weight, preferably 0.02 to 2% by weight, based on the total amount of polybutylene terephthalate and acrylic rubber. If it is too small, the effect will be small. On the other hand, if the amount is too large, mechanical properties will be adversely affected. Carbodiimide compounds are produced, for example, by heating decarboxylation from isocyanate compounds, and specific examples include diphenylcarbodiimide, ditolylcarbodiimide,
Di(propylphenyl)carbodiimide, di(butylphenyl)carbodiimide, dinaphthylcarbodiimide, bis(dipropylphenyl)carbodiimide, polyphenylenecarbodiimide, polytolylenecarbodiimide, poly(propylphenylene)carbodiimide, poly(dipropylphenyl)carbodiimide Examples include poly(diphenylmethane)carbodiimide, poly(diphenylmethane)carbodiimide, and polynaphthylenecarbodiimide. The amount is 0.01 to 5% by weight, preferably 0.02 to 2% by weight, based on the total amount of polybutylene terephthalate resin and acrylic rubber.
If it is too small, the effect will be small. On the other hand, if the amount is too large, it will adversely affect mechanical properties, which is undesirable. As for the blending method, the components may be mixed in any order by a known method, such as a method of mixing and extruding using an extruder or the like. Furthermore, in order to improve adhesion with fibrous reinforcing materials such as glass fibers, carbon fibers, and metal whiskers, and resins, it is more preferable to use a fibrous reinforcing agent whose surface has been treated with epoxy, epoxysilane, or aminosilane. The amount ranges from 5 to 50%, preferably from 7.5 to 30% by weight of the composition. Also,
Combustion dripping prevention agents such as asbestos, silica, alumina, silica alumina, silica magnesia, titania, calcium carbonate, talc, gypsum, and fillers such as glass flakes and glass beads, dyes and paraffins, fatty acid esters, lubricants such as fatty acid metal salts and bisamides;
Further, flame retardant aids such as Br compound flame retardants and antimony compounds may be used in combination for flame retardancy. An insert molded product is a composite molded product in which a metal or the like is attached in advance to a molding die, and the outside of the mold is filled with the above-mentioned blended resin composition. Molding methods for filling a mold with resin include injection, extrusion and compression molding, and injection molding is common. Furthermore, since the material to be inserted into the resin is used to take advantage of its properties and compensate for the defects of the resin, it must be one that does not change shape or melt when it comes into contact with the resin during molding. For this reason, metals such as aluminum, magnesium, steel, iron, steel, and their alloys, and inorganic solids such as glass and ceramics, which are preformed into rods, pins, screws, etc., are mainly used. Ru. [Examples] The present invention will be specifically explained below using Examples, but the present invention is not limited to the following Examples unless the gist thereof is exceeded. Example 1, Comparative Example 1 A copolymer obtained by polymerizing polybutylene terephthalate with an intrinsic viscosity of 1.10, 69.3 parts of butyl acrylate, 0.35 parts of butylene diacrylate, and 0.35 parts of diallyl maleate was added with 30 parts of methyl methacrylate.
and glass fiber (manufactured by Asahi Fiberglass Co., Ltd.).
CS03MA486) was mixed in the proportions shown in Table 1 to prepare a mixture, which was then melt-kneaded at 260°C using a 40 mmφ extruder and extruded into pellets. The pellets were placed vertically in a 3.9-ounce injection molding machine (manufactured by Japan Steel Works, Model N-100B) and a test piece mold (18 mm long, 16 mm wide, and 50 mm high) inside a box-shaped box.
The resin temperature is 270℃, the mold temperature is 80℃,
Injection molding was performed with an injection time of 15 seconds and a cooling time of 20 seconds. The obtained molded product was subjected to a high and low temperature impact test (-40℃ x 2 hours after cooling, the temperature was raised to 130℃ within 5 minutes for 2 hours using a thermal shock tester (Tabai Spec Co., Ltd. TSC-203 model). After heating, the process of further cooling to -40°C was defined as one cycle), and the number of cycles at which cracks occurred in the resin was measured. The results were as shown in Table 1 below. For comparison, the results obtained when no acrylic rubber was blended are also shown.

[Table] Examples 2, 3, Comparative Examples 2, 3 The composition of Example 1 (polybutylene terephthalate resin mixed with acrylic rubber and glass fiber) was added with an epoxy compound (bisphenol A-diglycidyl ether, Adeka Argus). A mixture (Example 2) of a chemical product trademark mark Ep-17) and an ester of pentaerythritol [pentaerythritol tetrakis (dodecylthiopropionate), Mitsubishi Yuka Co., Ltd. trademark Senox 412S];
Furthermore, a mixture (Example 3) in which bis(diisopropylphenyl)carbodiimide was added to these mixtures was mixed in the proportions shown in Table 2, pelletized and molded in the same manner as in Example 1, and subjected to a high-temperature impact test. The results are shown in Table 2. For comparison, the results when no acrylic rubber was blended are also shown.

〔Effect of the invention〕

As described above, the insert molded product according to the present invention has excellent high and low temperature impact resistance, which is about 10 times that of polybutylene terephthalate when subjected to heat cycles, and is particularly useful in the automobile field.

Claims (1)

[Claims] 1. Acrylic rubber 1 obtained by graft polymerizing a graft polymer monomer to a polymer obtained by polymerizing 99 to 50 parts by weight of polybutylene terephthalate, an acrylic ester, and a small amount of a crosslinking monomer. An insert-molded product formed by insert-molding a resin composition comprising ~50 parts by weight and a metal or inorganic solid. 2 Consists of an acrylic rubber obtained by graft polymerizing a graft polymerizable monomer to a polymer obtained by polymerizing polybutylene terephthalate, an acrylic acid ester, and a small amount of a crosslinking monomer, and a fibrous reinforcing agent and/or an epoxy compound. The insert molded article according to claim 1, characterized in that a resin composition is used. 3 Acrylic rubber obtained by graft polymerizing a graft polymerizable monomer to a polymer obtained by polymerizing polybutylene terephthalate, an acrylic acid ester, and a small amount of a crosslinking monomer, an epoxy compound, a pentaerythritol ester, and further fibrous reinforcement. characterized by using a resin composition consisting of an agent and/or a carbodiimide compound,
An insert molded product according to claim 1.