WO2018047473A1 - Polyacetal resin-nitrile rubber composite - Google Patents

Abstract

A polyacetal resin-nitrile rubber composite wherein, on a blasted surface of a polyacetal resin molded article, an undercoating adhesive layer formed of an undercoating adhesive, said undercoating adhesive comprising (a) poly(para-vinyl phenol), (b) 2.5-20 parts by weight, per 100 parts by weight of the poly(para-vinyl phenol), of an epoxy resin, (c) 0.2-7 parts by weight, per 100 parts by weight of the epoxy resin, of an imidazole compound and (d) 3-20 parts by weight, per 100 parts by weight of the total content of the poly(para-vinyl phenol) and the epoxy resin, of silica optionally mixed with a metal oxide, a top coating adhesive layer containing a polyolefin-based resin, and a nitrile rubber layer are successively laminated. In this composite, the polyacetal resin having excellent properties is firmly adhered to the nitrile rubber.

Description

Polyacetal resin-nitrile rubber composite

The present invention relates to a polyacetal resin-nitrile rubber composite. More specifically, the present invention relates to a polyacetal resin-nitrile rubber composite that is attached to an output shaft coupling portion of a propeller shaft and a transmission and is effectively used for a sliding bearing, a centering bush that functions as a vibration-proof bushing, and the like.

Polyacetal resins are used in various fields due to their excellent fatigue resistance, balanced properties such as friction resistance, wear resistance, low noise, chemical resistance, creep resistance, and dimensional stability. However, due to its special chemical structure, it has a problem that it has poor affinity with rubber or the like compared to other engineering plastics, and it is difficult to compound with rubber or the like.

When a polyacetal resin and rubber are vulcanized and bonded, the surface of the polyacetal resin molded article is subjected to sequential blasting and phosphoric acid surface treatment, containing synthetic resin, chlorinated rubber resin and metal oxide. There has been proposed a method of applying an undercoat adhesive and applying an overcoat adhesive containing a polyolefin resin (Patent Document 1).

Conventionally used undercoat adhesives cannot secure the chemical and physical bonding strength with the surface of a molded article of polyacetal resin that has been subjected to blasting only, and peel off between the polyacetal resin and the undercoat adhesive layer. There was a problem that would occur.

On the other hand, phosphating after blasting improves chemical and physical bonding strength and improves adhesion, but phosphating using strong acid is preferable because it is dangerous in terms of work safety. Absent.

JP 63-175038 A US Pat. No. 5,318,813 US Pat. No. 5,344,882 US Pat. No. 5,286,807

An object of the present invention is to provide a composite in which a polyacetal resin having excellent physical properties and a nitrile rubber are firmly bonded.

An object of the present invention is to provide (a) polyparavinylphenol, (b) 2.5 to 20 parts by weight of an epoxy resin with respect to 100 parts by weight of polyparavinylphenol on the surface of a blasted polyacetal resin molded article, (c) 0.2 to 7 parts by weight of imidazole compound and (d) silica or a mixture of silica and a metal oxide with respect to 100 parts by weight of epoxy resin with respect to 100 parts by weight of the total amount of polyparavinylphenol and epoxy resin An undercoat adhesive layer prepared from 3 to 20 parts by weight of silica or a mixture of silica and a metal oxide; an undercoat adhesive layer made of a polyolefin resin; and a nitrile rubber layer This is achieved by a polyacetal resin-nitrile rubber composite that is sequentially laminated.

The polyacetal resin-nitrile rubber composite according to the present invention has an excellent effect that a polyacetal resin molded article subjected only to blast treatment and nitrile rubber can be firmly bonded without performing etching treatment with phosphoric acid. Play.

Also, in the manufacturing process of the polyacetal resin-nitrile rubber composite, a strong acid is used, and therefore, an etching process using phosphoric acid, which is a dangerous operation, is not required, and the manufacturing process can be made safer and simplified.

Examples of the polyacetal resin include polyoxymethylene compositions described in Patent Documents 2 to 4, and in practice, commercially available products, DuPont product Delrin, BASF product ULTRA 製品 FORM, and the like are used.

The surface of the polyacetal resin molded article is blasted by sandblasting and then coated with an undercoat adhesive containing polyparavinylphenol, epoxy resin, imidazole compound and silica or a mixture of silica and a metal oxide.

Polyparavinylphenol is a polymer of paravinylphenol, and a commercially available product such as Maruzen Petrochemical product Maruka Linker M can be used as it is.

The epoxy resin can be used without particular limitation as long as it has two or more epoxy groups in one molecule, for example, bisphenol A type, low or high brominated bisphenol A type, bisphenol F type, phenol novolac type. Epoxy resins such as glycidyl ether types such as brominated phenol novolak type and cresol novolak type, glycidyl ester type, glycidyl amine type, alicyclic and heterocyclic can be used alone or in combination.

Preferably, glycidylamine type epoxy resin is used in an amount of 2.5 to 20 parts by weight, preferably 5 to 10 parts by weight, based on 100 parts by weight of polyparavinylphenol. If the amount of the epoxy resin is less than this, the undercoat adhesive itself is insufficiently cured and the adhesive force with the polyacetal resin is reduced. On the other hand, if it is used more than this, the polyacetal resin has a high affinity. The content ratio of paravinylphenol decreases, and the adhesiveness with the polyacetal resin is also insufficient.

Examples of the epoxy resin curing accelerator include 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-phenylimidazole, 1-benzylimidazole, 1-benzyl. Imidazole compounds such as -2-methylimidazole, 2,4-diamino-6- [2-methylimidazoline- (1)]-ethyl-s-triazine are used, and this is 0.2 to 100 parts by weight of epoxy resin. 7 parts by weight, preferably 0.25 to 5 parts by weight are used. If the curing accelerator is used less than this, the undercoat adhesive becomes insufficiently cured, and the adhesive strength with the polyacetal resin is reduced. On the other hand, if it is used more than this, it will be cured too much and adhesion with the topcoat adhesive will occur. Sexuality begins to decline.

Further, silica (silicon oxide) or a mixture of silica and a metal oxide as a filler is 3 to 20 parts by weight, preferably 5 to 10 parts by weight with respect to 100 parts by weight of the total amount of polyparavinylphenol and epoxy resin. Used. If less filler is used, the adhesive may flow during product molding, whereas if more filler is used, the adhesion of the undercoat adhesive to the polyacetal resin will be reduced.

Here, colloidal silica is used as the silica, which is in a state of being dispersed in an organic solvent such as methanol, methyl ethyl ketone, methyl isobutyl ketone. Examples of the metal oxide include zinc oxide, titanium oxide, magnesium oxide, and a mixture thereof. These are used in a weight ratio of 3 or less with respect to the silica 1.

These components are dissolved or dispersed in an organic solvent to prepare an undercoat adhesive. The organic solvent is used in an amount of about 400 to 3500 parts by weight with respect to 100 parts by weight of the solids so that the solid content concentration of the undercoat adhesive is about 3 to 20%.

The undercoat adhesive prepared by mixing the above components is about 2.5 to 25 mg / m 2 by immersing, spraying, brushing, roll coating or the like on the surface of a blasted polyacetal resin molding. ² , preferably about 6 to 15 mg / m ² , coated on one side (weight per unit area), dried at room temperature or warm air, and then baked at about 80 to 150 ° C. for about 1 to 20 minutes. When the coating amount is larger than this, cohesive failure occurs in the undercoat adhesive layer, whereas when the coating amount is smaller than this, the adhesiveness with the top coating adhesive is lowered. .

An adhesive containing a polyolefin resin or the like is applied as an overcoat adhesive on the undercoat adhesive layer that has been applied on the polyacetal resin molded article and has been subjected to a drying treatment. As the polyolefin resin, those based on modified polyolefin such as modified polyethylene obtained by introducing a functional group into polyolefin and imparted adhesive properties, modified polypropylene, and the like, preferably those based on modified polyethylene are used.

Polyolefin-based topcoat adhesives are generally alcohol-based organic solvents such as methanol, ethanol, and isopropanol, ketone-based organic solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, or aromatic organic solvents such as toluene and xylene, alone or as a mixed solvent. As an organic solvent solution having a component concentration of about 10 to 20% by weight, it is applied with a weight per side (applied amount) of about 5 to 20 mg / m ² by the same application method as in the case of the undercoat adhesive. After being dried at room temperature or warm air, it is baked at about 60 to 120 ° C. for about 1 to 20 minutes.

On the adhesive layer thus formed, an unvulcanized nitrile rubber compound is applied as an organic solvent solution of the rubber compound so that a vulcanized material layer having a thickness of about 5 to 120 μm is formed on one side. Is done.

Nitrile rubber (NBR) can be used as a compound using an organic peroxide, but sulfur-based vulcanizing agents such as sulfur, tetramethylthiuram monosulfide, tetramethylthiuram disulfide, etc. are preferably used. Used as an unvulcanized nitrile rubber compound compounded at a ratio of about 0.2 to 2 parts by weight per part by weight. Examples of such sulfur vulcanized unvulcanized nitrile rubber compounds include the following blending examples.

(Formulation example)
NBR (Nippon Zeon product NIPOL 1042) 100 parts by weight Carbon black (Nippon Nikkei carbon product NITERON # 10) 40 〃
Hydrous Magnesium Silicate (Asada Milling Product SW-H) 30 〃
Activated zinc flower (Zodo Chemical Industry Product AZO) 5)
Stearic acid (Miyoshi oil and fat product stearic acid TST) 2 〃
Coumarone-indene copolymer resin 5 〃
(NITTO RESIN G-90)
Wax (Ouchi Emerging Chemical Industries SUNNOC) 1 1
Anti-aging agent (ANTAGE OD-P, Kawaguchi Chemical Industries product) 1 〃
Plasticizer (Idemitsu Kosan product DIANA PROCESS OIL AH-16) 10 〃
Sulfur (Tsurumi Chemicals colloidal sulfur) 1
Vulcanization accelerator (Ouchi Emerging Chemical Industry Noxeller TT-P) 2〃
Vulcanization accelerator (Corporate product Noxeller CZ-P) 3 〃
Vulcanization is carried out under pressurized conditions at about 160-200 ° C. for about 3-8 minutes.

Next, the present invention will be described with reference to examples.

Example 1
After applying an undercoat adhesive solution having the following composition at a thickness of 10 μm (weight per unit area 8 mg / m ² ) on the surface of a molded article of sandblasted polyacetal resin (BASF product ULTRA FORM), and drying at room temperature Baked at 120 ° C. for 10 minutes.
47.5 parts by weight of polyparavinylphenol (Maruzen Petrochemical Marca Linker M)
Glycidylamine type epoxy resin (Mitsubishi Chemical JER630) 2.5 〃
Imidazole compound (Shikoku Chemicals 2E4MZ) 0.13 〃
Methyl ethyl ketone 1033 〃
Colloidal silica 30% by weight methyl ethyl ketone solution 16.7
(Nissan Chemical Industrial products Snowtex MEK-ST)

Next, a topcoat adhesive solution having the following composition was applied at a thickness of 15 μm (weight per unit area: 14 mg / m ² ), dried at room temperature, and then baked at 80 ° C. for 5 minutes.
100 parts by weight of polyolefin resin adhesive (Chemlok 6108 from Road Far East)
Toluene 5 〃
Xylene 28 〃

A nitrile rubber compound (formulation example I) is bonded onto the adhesive layer thus formed, and pressure vulcanization is performed at 145 ° C. for 7 minutes to form a nitrile rubber layer, and polyacetal resin-nitrile A rubber composite was obtained.

When the obtained polyacetal resin-nitrile rubber composite was subjected to an adhesion test, the rubber residual area ratio was 100%. Here, the adhesion test was performed by performing a 90 ° peel test and calculating a rubber residual area ratio in accordance with JIS K6256-2 corresponding to ISO 813.

Example 2
In Example 1, when the amount of colloidal silica solution of the undercoat adhesive solution was changed to 2.3 parts by weight, and further 2.3 parts by weight of titanium oxide and 0.5 parts by weight of zinc oxide were used, the rubber residual area ratio by the adhesion test was 100%. Met.

Comparative Example 1
In Example 1, when the amount of polyparavinylphenol in the undercoat adhesive solution was changed to 50 parts by weight and the glycidylamine type epoxy resin and imidazole compound were not used, the rubber residual area ratio by the adhesion test was 70%. Peeling was observed between the polyacetal resin and the undercoat adhesive.

Comparative Example 2
In Example 1, the amount of polyparavinylphenol in the undercoat adhesive solution was changed to 37.1 parts by weight, the amount of glycidylamine type epoxy resin was changed to 12.9 parts by weight, and the amount of imidazole compound was changed to 0.67 parts by weight. According to the adhesion test, the rubber residual area ratio was 5%, and peeling was observed between the polyacetal resin and the undercoat adhesive.

Comparative Example 3
In Example 1, when the amount of methyl ethyl ketone in the undercoat adhesive solution was changed to 950 parts by weight and no colloidal silica was used, the rubber residual area ratio by the adhesion test was 80%, and the polyacetal resin and the undercoat adhesive There was peeling between them.

Comparative Example 4
In Example 1, when the amount of methyl ethyl ketone in the undercoat adhesive solution was changed to 1200 parts by weight and the amount of colloidal silica solution was changed to 50 parts by weight, the rubber residual area ratio by the adhesion test was 50%, and polyacetal Peeling was observed between the resin and the primer adhesive.

Comparative Example 5
In Example 1, 100 parts by weight of a chlorinated rubber-based adhesive (Chemlok 205 manufactured by Road Far East Co.) and 14.2 parts by weight of methyl ethyl ketone were used as the undercoat adhesive solution. The rubber residual area ratio according to the adhesion test was 20%. Peeling was observed between the polyacetal resin and the undercoat adhesive.

From the above results, the following can be said.
(1) In Examples 1 and 2, there was no problem in adhesiveness, and the rubber residual ratio was 100%.
(2) When an epoxy resin was not used as an undercoat adhesive component, the undercoat adhesive itself was insufficiently cured, resulting in a decrease in adhesive strength, resulting in a rubber residual ratio of 70% (Comparative Example 1).
(3) When an epoxy resin is used in a specified amount or more as an undercoat adhesive component, the content of polyparavinylphenol having a high affinity with the polyacetal resin is reduced, and the adhesion between the polyacetal resin and the undercoat adhesive is reduced. The force was insufficient, and the rubber residual ratio was 5% (Comparative Example 2).
(4) When no filler is used as the undercoat adhesive component, the undercoat adhesive is washed away, resulting in a rubber residual ratio of 80% (Comparative Example 3).
(5) When the filler is used in a predetermined amount or more as an undercoat adhesive component, the adhesive strength of the undercoat adhesive to the polyacetal resin surface is reduced, and the rubber residual ratio becomes 50% (Comparative Example 4).
(6) In the case of a conventionally used adhesive, the adhesive strength to a polyacetal resin not subjected to phosphoric acid treatment is reduced, and the rubber residual ratio is 20% (Comparative Example 5).

In the polyacetal resin-nitrile rubber composite according to the present invention, since the polyacetal resin and the nitrile rubber are firmly bonded, they are mounted on the output shaft connecting portion between the propeller shaft and the transmission and function as a slide bearing and a vibration-proof bushing It is effectively used for centering bushes.

Claims (6)

(A) Polyparavinylphenol, (b) 2.5-20 parts by weight of epoxy resin with respect to 100 parts by weight of polyparavinylphenol, (c) 100% by weight of epoxy resin 0.2 to 7 parts by weight of imidazole compound and 3 to 20 parts by weight of silica or (d) silica or a mixture of silica and metal oxide for 100 parts by weight of the total amount of polyparavinylphenol and epoxy resin Alternatively, a polyacetal resin formed by sequentially laminating an undercoat adhesive layer prepared from an undercoat adhesive containing a mixture of silica and a metal oxide, an overcoat adhesive layer containing a polyolefin resin, and a nitrile rubber layer -Nitrile rubber composite. 2. The polyacetal resin-nitrile rubber composite according to claim 1, wherein the epoxy resin is a glycidylamine type epoxy resin. 2. The polyacetal resin-nitrile rubber composite according to claim 1, wherein the silica is colloidal silica. 2. The polyacetal resin-nitrile rubber composite according to claim 1, wherein the undercoat adhesive is prepared as an organic solvent solution or dispersion. The polyacetal resin-nitrile rubber composite according to claim 1, 2, 3 or 4, which is used for a centering bush. A centering bush manufactured using the polyacetal resin-nitrile rubber composite according to claim 5.