JPH01272424A - Method for bonding insert resin molded product to injection resin - Google Patents

Abstract

PURPOSE:To manufacture an injection molded composite laminate having strong resistance against thermal and electric shocks, by using an acrylic copolymer aqueous emulsion having a specific composition as a primer. CONSTITUTION:A primer 6 is composed of an aqueous emulsion containing 35-75wt.% of alkyl acrylate having a 1-8C alkyl group, 10-50wt.% of alkyl methacrylate having a 1-4C alkyl group, 0-15wt.% of styrene and/or acrylonitrile, 0-5wt.% of a vinyl monomer selected from methacrylamide equivalent and 0-30wt.% of other vinyl monomer and applied to the surface of a resin molded product to be dried. The coated product is inserted in the cavity 3 of an injection mold 1 and a resin 7 is subsequently injected in the cavity 3 to unify the inserted resin molded product and the injected resin molded product through the primer 6.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is useful for ignition parts, automobile parts such as VVT valves, electrical parts such as connectors and CD parts, gasoline tanks, metal insert resin industrial parts, backings, etc. The present invention relates to a method of adhering resins that can be used when manufacturing a resin laminate.

[Prior art]

In recent years, a wide variety of thermoplastic plastics have appeared, including engineering plastics (polyamide, polyester, polycarbonate, polyacetal, polysulfone, polysilicon, polyphenylene oxide,
Polyimide, ABS.

Resins called methacrylic (methacrylate, etc.) are manufactured and sold, and many of these resins exhibit excellent mechanical strength, heat resistance, creep resistance, chemical resistance, electrical properties, dimensional stability, etc., and are widely used. Under certain conditions, there are many substitutes for metals such as iron, zinc, and aluminum.

For example, polyamide is used as a material for gasoline tanks.

Depending on the application of the product, some products cannot be molded with a single mold, so a resin part with a metal insert is pre-molded, this is installed in the cavity of an injection mold, and then the same or different types of molten parts are molded. Insert parts molded from resin materials, such as laminates obtained by injecting resin, or composite products that integrate resin pipes and resin joints, such as female threads and coils with complex shapes, are placed in injection molds. Mounting and then injecting molten resin to integrate are carried out.

Conventionally, in order to improve the adhesion between the insert parts and the injection resin, liquid adhesives or primers were applied to the surface of the insert resin molded product, or the surface of the rubber molded product was treated with trichlene or trichloroisocyanuric acid. It is then injection molded and composited.

The liquid adhesives and primers include solvent-type polyester resins, liquid epoxy resins, and metal salts of ethylene/methacrylic acid copolymers (Zn'', Na'', K0).
, maleic anhydride grafted ethylene/vinyl acetate copolymer, polyester aqueous emulsion, polyvinyl acetate aqueous emulsion, liquid phenolic resin, etc. are used.

Recently, in fields where the insert resin parts further contain metal, have complex shapes, and require pressure resistance and thermal shock resistance depending on the use of the composite, adhesive strength has increased even with the same type of resin. It has been pointed out that adhesive strength is insufficient even when adhesives or primers are used, and problems such as leakage and breakage occur.

This problem has been pointed out particularly in fields where composite products are small and precision is required.

Currently, the bonded parts of these composite products are coated with epoxy resin or vulcanized polysilicone, but this prevents thermal shocks caused by repeated temperature changes due to the rise and fall of motor oil, temperature, etc., and electrical precision parts. Electric shock during voltage load, pressurization of motor oil, water, etc. (0.5~3
kg/cj), this coating becomes useless in a short period of time, and boundary peeling occurs between the bonded surface and the coated surface, causing liquid leakage, malfunction of precision mechanical parts and electronic parts, or making them inoperable.

[Specific measures to solve the problem]

In the present invention, by using an aqueous acrylic copolymer emulsion having a specific composition as a primer (adhesive), an injection molded composite laminate that is resistant to thermal shock and electric shock can be manufactured.

That is, the present invention provides, on the surface of a resin molded article, (a) 35 to 75% by weight of an acrylic acid alkyl ester having an alkyl group having 1 to 8 carbon atoms; (b) having an alkyl group having 1 to 4 carbon atoms; Methacrylic acid alkyl ester 10-50% by weight (C) Styrene and/or acrylonitrile 0-50% by weight
15% by weight However, the sum of component (b) and component (C) is 15 to 55% by weight.

(d) α, β-unsaturated acid or its acid anhydride, 2-
0 to 5% by weight of a vinyl monomer selected from hydroxyethyl acrylate, 2-hydroxypropyl acrylate, or their methacrylate equivalents, acrylamide, methylolacrylamide, or their methacrylamide equivalents (e) Other vinyl monomers A primer consisting of an aqueous emulsion of a copolymer with a glass transition point (Tg) of 20°C or less obtained by emulsifying a monomer mixture consisting of 0 to 30% by weight is coated and dried, and then molded into an injection mold. To provide an adhesion method characterized by inserting a resin molded product into a cavity of a mold, then injecting a resin into the cavity, and integrating the inserted resin molded product and the injected resin molded product via the primer. It is something.

Hereinafter, the present invention will be explained using the drawings.

In FIG. 1, 1 is an injection mold, 1a is a fixed mold, 1b is a movable mold, the movable mold 1b is equipped with a release bottle, and the molds 1a and 1b form a cavity 3. Reference numeral 4 denotes an insert resin molded product equipped with a copper wire coil 5. A primer layer 6 is provided on at least the peripheral surface of the side surface that adheres to the injection resin 7, and this insert resin molded product 4 is attached to the movable mold 1b. It is fixed in cavity 3.

The fixed mold 1 a is connected to a plasticized resin 9 through a resin passage 8 , and the resin passage 8 is connected to the cavity 3 .

The molten resin 7 injected by an injection molding machine at a resin pressure of 500 to 2,000 kg/-0 fills the cavity 3 and is integrated with the insert resin molded product to form a composite molded product.

Therefore, the material resins of the resin molded product 4 to be inserted include polyamide, polyacetal, polybutylene terephthalate, polyethylene terephthalate, polyolefin, polyvinyl chloride, polycarbonate, polysulfone, epoxy resin, polyimide, modified polyphenylene oxide, unsaturated polyester, and thermoplastic resin. One or a mixture of two or more resins selected from plastic polyurethane and vulcanized rubber is used.

These may contain fillers, pigments, stabilizers, flame retardants, UV absorbers, etc.

The resins to be injected next include polyamide, polyacetal, polybutylene terephthalate, polyethylene terephthalate, polyolefin, polycarbonate, modified polyphenylene oxide, thermoplastic polyurethane, vulcanized rubber, polymethyl methacrylate, polystyrene, A
Thermoplastic resins such as BS, thermosetting resins such as reactive epoxy resins, and novolac resins are used.

Furthermore, the rubber component of the vulcanized rubber used in the present invention is a natural rubber (NR) and a synthetic rubber having a carbon-carbon double bond in the structural formula, either alone or in a blend of two or more. The above synthetic rubbers include isoprene, butadiene,
Polyisoprene rubber (IR), which is a homopolymer of conjugated diene compounds such as chloroprene, and polybutadiene rubber (B
R), polychloroprene rubber, etc., styrene-butadiene copolymer rubber ( SBR), vinyl pyridine butadiene styrene copolymer rubber, acrylonitrile butadiene copolymer rubber, acrylic acid butadiene copolymer rubber, methacrylic acid butadiene copolymer rubber, methyl acrylate butadiene copolymer rubber, methyl methacrylate butadiene copolymer rubber, etc. , copolymers of olefins such as ethylene, propylene, and isobutylene and diene compounds, such as isobutylene isoprene copolymer rubber (nR)
, copolymers of olefins and non-conjugated dienes (EPDM
) For example, ethylene, propylene, cyclopentadiene terpolymer, ethylene propylene-5-ethylidene-2
-norbornene terpolymer, ethylene propylene-1
゜4-hexadiene terpolymer, polyalkenamer obtained by ring-opening polymerization of cycloolefin, such as polypentenamer, rubber obtained by ring-opening polymerization of oxirane ring, such as polyepichlorohydrin rubber and polypropylene oxide that can be sulfur-cured. Includes rubber, etc. Also included are halogenated products of the various rubbers mentioned above, such as chlorinated isobutylene isoprene copolymer rubber (CI-nR) and brominated isobutylene isoprene copolymer rubber (Br-IIR).

Furthermore, ring-opened polymers of norbornene can also be used.

In addition to sulfur vulcanization, which is most important in boat fishing, vulcanized rubber can also be produced by vulcanization with organic sulfur compounds, such as dithiodimorpholine, thiuram vulcanization, peroxide vulcanization, quinoid vulcanization, resin vulcanization, Metal salt vulcanization, metal oxide vulcanization, polyamide vulcanization,
It includes all those obtained by radiation vulcanization, hexamethylenetetramine vulcanization, etc.

(Primer) The aqueous resin emulsion forming the adhesive layer contains (a) 35 to 75% by weight of an acrylic acid alkyl ester having an alkyl group having 1 to 8 carbon atoms, and (medium) methacrylic acid having an alkyl group having 1 to 4 carbon atoms. Acid alkyl ester 10-50% by weight (C) Styrene and/or acrylonitrile 0-1
5% by weight However, the sum of component (b) and component (C) is 15 to 55% by weight.

(d) selected from α, β-unsaturated acids or their acid anhydrides, 2-hydroxyethyl acrylate, 2-hydroxybrobyl acrylate or their methacrylate equivalents, acrylamide, methacrylamide, methanolacrylamide, methacool methacrylamide; Other vinyl monomers 0 to 5% by weight (e) Other vinyl monomers 0
This is a copolymer emulsion obtained by emulsifying a monomer mixture of ~30% by weight, and the glass transition point of the copolymer is 20°C or lower.

(As the acrylic acid alkyl ester of the al component, 2-ethylhexyl acrylate (-85°C), n-butyl acrylate (-54°C), ethyl acrylate (-22°C)
), isopropyl acrylate (-5°C), methyl acrylate (8°C), and the like. In addition, the temperature in parentheses is
The Tg of the homopolymer of acrylic acid alkyl ester is shown.

This component (a) imparts flexibility to a film formed from an emulsion copolymer obtained from a soft monomer. The flexibility of this film allows it to follow the expansion and contraction caused by the difference in thermal expansion coefficients between the resins.

Component (b) methacrylic acid alkyl ester and (c)
Ingredients: styrene (100℃), acrylonitrile (10℃)
0°C) is called a hard monomer, which imparts toughness and heat resistance to the film. It is necessary that this hard monomer accounts for 15 to 55% by weight of the monomer mixture to form the copolymer. As a component, methyl methacrylate (
(105°C), ethyl methacrylate (65°C), n-butyl methacrylate (20°C), etc. can be used. From the viewpoint of adhesion, it is necessary that this component be contained in an amount of 10% by weight or more.

The upper limit of the amount of methacrylic acid alkyl ester in the monomer mixture of component (b) is 55% by weight. If this value is exceeded, the film becomes hard and brittle, and is likely to peel off due to thermal shock, or pinholes will occur in the film.

The proportion of component (c), styrene and acrylonitrile, in the monomer mixture is 15% by weight or less.

If it exceeds 15% by weight, the adhesion of the film to the adherend will decrease. Furthermore, in the case of acrylonitrile, if the amount used is large, emulsion polymerization is difficult to perform.

(The acid of the dl component and the vinyl monomer having a hydroxyl group or an amino group improve the adhesion of the film to the adherend (injection resin, insert resin molded product).

Examples of such acids include acrylic acid, methacrylic acid, itaconic acid, maleic acid, and maleic anhydride.

β-unsaturated acids or their acid anhydrides can be used.

These vinyl monomers having functional groups such as acid, hydroxyalkyl acrylate, acrylamide, and methylol acrylamide are used in an amount of 5% by weight or less, preferably 0.3 to 3% by weight of the monomer mixture.

Component (e) is used as necessary to adjust the balance between elasticity and toughness of the film and the glass transition point of the emulsion copolymer to 20° C. or lower.

Such monomers include butanediol diacrylate,
Butanediol monoacrylate, vinyl chloride, vinyl acetate (30°C), glycidyl methacrylate, etc. can be used. The component (e) monomer is used in an amount of 30% or less of the copolymer component.

A copolymer emulsion for forming an adhesive layer can be obtained according to a conventional method. That is, emulsion polymerization can be carried out in a system of monomers, surfactants, polymerization initiators, and water (in that case,
Preferably, the monomer concentration is 40 to 60% by weight based on the total amount, the surfactant is 1 to 5 parts by weight, and the polymerization initiator is 0.1 to 0.6 parts by weight based on 100 parts by weight of the monomer. It's the amount.

A surfactant should be selected that can smoothly carry out emulsion polymerization, especially one with an added mole number of oxyethylene groups of 10 to 60.
A mixed system of polyoxyethylene alkyl ether or polyoxyethylene alkyl phenol ether and higher alcohol sulfate ester salt, polyoxyethylene alkyl sulfate salt, or polyoxyethylene alkyl phenyl sulfate salt within the range of is preferable, and the polymerization initiator is persulfuric acid. Particularly preferred are potassium, ammonium persulfate, and redox systems containing these in combination with reducing agents. Note that it is preferable to adjust the pH value of the produced copolymer emulsion to 7 or more with aqueous ammonia or the like in order to improve dispersion stability.

The glass transition temperature (T) of the copolymer in the copolymer emulsion
g) is below 20°C. When Tg exceeds 20°C, the drying time of the film becomes longer. - In fact, the higher the Tg of the copolymer, the higher the strength of the film, and the lower the Tg, the higher the elasticity of the film.
Flexibility is high (it tends to be).

(Composite laminate) The above primer is applied to the surface of a pre-formed resin molded product at a rate of 10 to 100 glrd, and after drying, it is placed inside the cavity of a mold preheated to 40 to 120°C. molten thermoplastic resin (including vulcanizable rubber) or reactive thermosetting resin into the mold cavity.
A composite laminate is obtained by injection at an injection pressure of 0.00 to 1,500 kg/d.

Examples of preferable injection temperatures are as follows.

Polyamide (250-290℃), polyacetal (1
90-220℃), polybutylene terephthalate (25
0~270℃), polycarbonate (260~300℃)
), polyethylene terephthalate (250-270℃)
, polypropylene (180-230°C), and polyvinyl chloride (180-230°C). The injection pressure of the reactive thermosetting resin is 500 to 1.500 kg/aj,
The temperature is from room temperature to 130°C.

Next, the present invention will be specifically explained using Examples and Comparative Examples.

Example 1 Temperature regulator, anchor stirrer, reflux condenser, supply container,
The following raw materials were charged into a reaction vessel equipped with a thermometer and a nitrogen inlet tube.

200 parts of water 35% of the sodium salt of the sulfuric acid half ester of p-nonylphenol (anionic emulsifier) reacted with 20 moles of ethylene oxide 5 parts of water 20% of p-nonylphenol (nonionic emulsifier) reacted with 25 moles of ethylene oxide 20 parts of solution Next, after purging the inside of the reaction vessel with nitrogen gas, the following feed ■
was added and the mixture was heated to 90°C.

Feed I Water 200 parts 35% aqueous solution of the above anionic emulsifier 25 parts Methyl methacrylate 160 parts (40wtχ) n-butyl acrylate 204 parts (51tχ) Acrylic acid
20 parts (5wtχ) acrylamide 16
part (4-tχ).

Additionally, after charging 10% of 2.5 parts of potassium persulfate dissolved in 85 parts of water (Feed ■) into the container, the remaining Feed I total and 4 parts% of Feed ■ was fed into the container over a period of 3.5 hours, and after the feeding was completed, the feed was kept at the same temperature for 2 hours to polymerize the feed (1) to obtain an anionic resin aqueous emulsion (Tg 3°C).

This emulsion was applied to the coil bobbin resin molded product of the electromagnetic valve shown in Fig. 1, in which the coil was secured to nylon 66.
4) was applied to the peripheral surface of the side wall so that the solid amount was 30 g/l, and after drying for 2 hours, it was put into an injection mold (70 g/l).
℃) into the cavity of a moving mold as shown in Fig.
The composite laminate shown in FIG. 2 was obtained by pressure injection molding.

The composite laminate has an outer diameter of 25 nm, a height of 35 mm, a nylon 6 wall thickness of 1 fl, and a cylindrical shape.

(a) Injection nylon 6 at 20°C of this composite laminate
The airtightness of the inserted nylon 66 makes it possible to secure the composite laminate with fasteners (13a, 13b) as shown in Figure 3.
The primer layer (6) of the composite laminate is placed in a water tank (14) containing water (15) using backings (12a, 12b) to prevent water from entering from the outside, and air is pressurized from above. ) as a result of judging based on the presence or absence of bubbles, 6
Withstands pressurized air pressure of kg/cd.

Furthermore, after this composite laminate was immersed in a 100° C. motor oil bath for one day, its airtightness withstood an air pressure of 5 kg/cut.

Furthermore, this composite laminate was placed in (c) a motor oil bath at 20°C for 2 hours, and then the motor oil bath was heated to 80°C for 15 hours.
Heat for 3 minutes, continue soaking at the same temperature for 2 hours, and then continue soaking for 3 hours.
Composite after a thermal shock test in which the process of cooling the motor oil bath to 20℃ over 0 minutes, immersing it again at 20℃ for 2 hours, then heating it to 80℃, and continuing immersion at the same temperature for 2 hours was repeated 5 times. The airtightness of the laminate is 4
Withstands air pressure of kg/d.

Examples 2 to 6, Comparative Examples 1 to 3 Aqueous copolymer emulsions were obtained in the same manner as in Example 1, except that the type and amount of the vinyl monomer to be emulsion polymerized were changed as shown in Table 1. A composite laminate having the performance shown in Table 2 and Table 3 was obtained.

The peel test for this composite laminate was conducted in accordance with JIS K 6850.

(a) Peel strength at 20°C.

(b) Peel strength after being immersed in a 100°C motor oil bath for 1 day (c) Immersed in a 20°C motor oil bath for 2 hours, then heated the motor oil bath to 80°C over 15 minutes, and at the same temperature. The immersion was continued for 2 hours, and the motor oil bath was further cooled to 20°C over 30 minutes, and the motor oil bath was immersed again at 20°C for 2 hours.
Peel strength after repeating the process 5 times: heating to 80°C and continuing immersion at the same temperature for 2 hours.

Example 7 The insert resin molded product shown in Table 3 coated with the primer used in Example 1 was installed in the cavity of a moving mold,
Next, the resin shown in the table was injected into the cavity at the temperature and pressure shown in the table to obtain a composite laminate.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view of an injection molding apparatus, and FIG. 2 is a sectional view of a composite laminate. FIG. 3 is a partial sectional view of the device used for the airtightness test.

Claims (1)

[Scope of Claims] 1) On the surface of the resin molded article, (a) 35 to 75% by weight of an acrylic acid alkyl ester having an alkyl group having 1 to 8 carbon atoms (b) an alkyl group having 1 to 4 carbon atoms 10-50% by weight of methacrylic acid alkyl ester having (c) styrene and/or acrylonitrile 0-15%
Weight% However, the sum of component (b) and component (c) is 15 to 55% by weight. (d) selected from α, β-unsaturated acids or their acid anhydrides, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, or their methacrylate equivalents, acrylamide, methylolacrylamide, or their methacrylamide equivalents; A copolymer with a glass transition point (Tg) of 20°C or less obtained by emulsifying a monomer mixture consisting of 0 to 5% by weight of vinyl monomer (e) 0 to 30% by weight of other vinyl monomers. A primer consisting of an aqueous emulsion is applied and dried.
An adhesion method characterized by inserting a resin into a cavity of an injection mold, then injecting a resin into the cavity, and integrating the inserted resin molded product and the injected resin molded product via the primer. 2) The resin molded product to be inserted is made of polyamide, polyacetal, polybutylene terephthalate, polyethylene terephthalate, polyolefin, polyvinyl chloride,
Claim 1, characterized in that the material is made of a resin selected from polycarbonate, polysulfone, epoxy resin, polyimide, modified polyphenylene oxide, unsaturated polyester, thermoplastic polyurethane, and vulcanized rubber. Adhesion method. 3) The injected resin is polyamide, polyacetal,
Polybutylene terephthalate, polyethylene terephthalate, polyolefin, polycarbonate, epoxy resin, novolak resin, modified polyphenylene oxide,
2. The bonding method according to claim 1, wherein the resin is selected from thermoplastic polyurethane and vulcanizable rubber.