JPH07331187A - Adhesive composition for thread locking of screw member - Google Patents

Abstract

PURPOSE:To obtain an adhesive for thread locking which can form a stable coating film on a screw member by mixing a specified monomer such as methacrylate with microcapsules containing a polymerization initiator, a polymerization accelerator and a specified water-based binder. CONSTITUTION:This adhesive composition is prepared by mixing a monomer or oligomer (A) terminated with a polymerizable double bond with microcapsules (B) containing a polymerization initiator, a polymerzation acelerator (C) and a water-based binder (D) of the formula (wherein r is 1-4 Calkyl; 1 is 1-15; and m+n=85-99). It is desirable that component A is one having a water solubility of 10% or below, and, for example, bisphenol A (meth)acrylate is suitable. It is particularly desirable that the wall material of component B is melamine, and that the polymerization initiator is a diacyl peroxide. A tert. amine is used as component C. A specified polyvinyl acetal resin is used as component D. An aqueous solution of components A to D is previously applied to a screw member and dried to form a coated screw member which can be stored for long time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to self-locking for application to a screwing surface of a screw member such as a screw, a bolt or a nut so as to prevent loosening and provide adhesion (hereinafter collectively referred to as loosening prevention). The present invention relates to an adhesive composition for screw members.

[0002]

2. Description of the Related Art Conventionally, an organic solvent or water is used as a solvent for reactive adhesion as a loosening-preventing adhesive applied to a screwing surface (screw) of a screwing member such as a screw, a bolt or a nut. A composition comprising a microcapsule containing an agent and a resin as a binder is disclosed in Japanese Examined Patent Publication Nos. 45-11051 and 52-4.
6339, JP-A-2-308876, JP-A-53-11883 and the like are known.

Further, JP-A-57-192476 discloses a loosening-preventing adhesive for the same purpose, which is a microcapsule containing a polymerizable monomer and a polymerization initiator, a polymerization accelerator and an aqueous binder of ethylene-maleic anhydride. A composition consisting of is disclosed.

Further, the applicant himself discloses as a technique similar to these, an adhesive composition comprising microcapsules containing an epoxy resin, an amine-based curing agent for the epoxy resin, and an aqueous binder comprising a water-soluble polyacetal. (Japanese Patent Laid-Open No. 5-140514).

[0005]

However, among these conventionally known microcapsule type adhesives, the type in which a reactive main agent and a reactive initiator (curing agent) are each microencapsulated is an adhesive agent. Although it has excellent storage stability as described above, there is a problem in cost because a large amount of microcapsules are used, and the adhesive strength itself is insufficient because the amount of the reactive main agent that can be used is limited. .

On the other hand, when the water-based binder is completely water-soluble, there are drawbacks such that it takes a long time to dry after coating the bolt and the productivity is extremely deteriorated.
The aqueous binder used in No. 140514 is moderately water-soluble, and problems such as long drying time are eliminated.

However, in the above-mentioned Japanese Patent Laid-Open No. 5-140514, microcapsules containing an epoxy resin and a curing agent are dissolved or dispersed in these aqueous binders, and the binder itself is partially dissolved in water. In order to manufacture a pre-coated bolt by applying it to the screwed part of and drying it,
Since the coating film formed after drying is hard and relatively brittle,
There is a problem that the coating film partly peels off when the bolts are tightened, and scraps are generated.

Further, in the above-mentioned JP-A-57-192476, a polymerizable monomer in which microcapsules are dispersed in an aqueous binder and a polymerization accelerator are in a suspended state in an emulsion state, and the binder itself is submerged in water. The partially-dissolved suspension state is applied to the threaded portion of the bolt or the like and dried to produce a pre-coated bolt. In this case, the stability of the emulsion state of the composition before application to the bolt or after application or after application The stability of the dried coating film was insufficient, and therefore, it was not possible to obtain a loosening preventive precoated bolt which can be stored for a long period of time.

[0008]

In view of the above situation, the present invention provides a precoat type adhesive composition for preventing loosening of a screw member, comprising: a) a monomer or oligomer having a polymerizable double bond at a terminal of a molecule; ) Microcapsules containing a polymerization initiator c) Polymerization accelerator d) Aqueous binder represented by the following formula

(Wherein R is an alkyl group having 1 to 4 carbon atoms, l is 1 to 1)
15, m + n = 85 to 99) for preventing loosening of a screw member.

That is, according to the present invention, the monomer or oligomer of a) in which the microcapsules of b) are dispersed and the polymerization accelerator of c) are suspended in the aqueous binder of d) before being applied to a bolt or the like. In addition, the aqueous binder of d) itself is partially dissolved in water and is in a suspension state, and after being applied to a bolt or the like, the microcapsules of b) are dispersed in the aqueous binder of d). The monomer or oligomer and the polymerization accelerator of c) are suspended and dispersed and fixed to a bolt or the like in an apparent solid state. In the present invention, by using the above-mentioned structural formula as the aqueous binder, It has been found that the above-mentioned state after coating can be kept stable over a long period of time.

Further, since the aqueous binder used in the present invention is partially dissolved in water to be in a suspended state, it becomes easy to dry, and an apparently dried coating film after being applied to bolts and the like can be obtained at an early stage. Like

The monomer or oligomer having a polymerizable double bond at the end of the molecule a) used in the present invention is preferably one having a solubility in water of 10% or less by weight, It is not limited to this.

Specifically, bisphenol A type (meth) acrylate or glycidyl (meth) acrylate is preferable.

Next, b) in the microcapsules containing the polymerization initiator, the polymerization initiator is peroxide,
Hydroperoxides, peresters and peramides can be used, preferably peroxides and more preferably diacyl peroxides.

Aldehyde resin or urea resin is used for the wall material forming the wall film of the microcapsule. Examples of the aldehyde resin include urea-formaldehyde resin and melamine-formaldehyde resin, and the urea resin is , Polyurea, polyurethane resin and the like, but melamine resin is particularly preferable.

The particle size of the capsule is several μm to 100 μm.
It can be used up to about m 2, but is preferably 20 to 60 μm.

As the polymerization accelerator c), conventionally known compounds such as amines and sulfimides can be used, but the invention is not limited thereto.

Specific examples include tertiary amines such as N, N dimethylparatoluidine and sulfimides such as 3-oxo-2,3-dihydrobenzisothiazole-1,1-dioxide. However, N, N dimethylparatoluidine is particularly preferred.

The d) aqueous binder is represented by the following general formula.

(Wherein R is an alkyl group having 1 to 4 carbon atoms, l is 1 to
15, m + n = 85 to 99), and is made by reacting polyvinyl alcohol with an aldehyde, preferably 1 in the above formula is 1 to 5, m is 10 to 14, and n is 80 to 87. Appropriate.

Specific examples of the above-mentioned aqueous binder include polyvinyl acetal resin Slex KW manufactured by Sekisui Chemical Co., Ltd.
A series is mentioned.

The above-mentioned compositions a) to d) are used as an aqueous solution after being applied in advance to a member having a threaded portion such as a bolt, a screw or a nut.

The prepared suspension is applied to a screwing portion such as a bolt by an automatic applicator or brush coating, and then the water content in the aqueous solution is evaporated and volatilized at room temperature or in a heating furnace to remove the bolt or the like. Fix it to the screwing surface of.

The above a) fixed to the bolt or the like in this way
The compositions (a) to (d) exist in a state in which a) and c) are dissolved and dispersed in d) and b) in a state dispersed in a), and are fixed to bolts in an apparent solid state.

When used, the microcapsules encapsulating the polymerization initiator of b) in the composition are destroyed by tightening with a nut or the like, and the polymerization initiator of the encapsulation flows out. On the other hand, this tightening causes the bolts and nuts to be fixed by polymerizing with the monomer or oligomer of a) that has exuded from the aqueous binder of d) and curing, but in the present invention, the composition is pre-coated on the bolts. In this state, the compositions a) to d) are extremely stable, and thus can be stored for a long period of time.

The above-mentioned suspension is appropriately adjusted depending on the size of bolts, screws, nuts and the like, the size of the coating surface, etc., and also the types and blending amounts of the substances a) to d) constituting the aqueous solution. Changes to.

In general, if the amount of the aqueous binder of d) is too large with respect to water, the amount of dust generated during tightening (when using a bolt or the like) is increased, and the adhesive strength is insufficient. On the contrary, it is too small. As a result, the good suspension state collapses, and after application to bolts, etc., it does not appear to be dry.

Furthermore, the amount of the microcapsules containing the polymerization initiator of b) and the amount of the polymerization accelerator of c) relative to the amount of the monomer or oligomer of a) are such that the monomer or oligomer of a) is polymerized and cured. However, it is preferable that the monomer or oligomer of a) is blended in a slight excess so as not to impair the stability of the monomer or oligomer.

As a preferred example of this aqueous solution, a microparticle containing 30 to 50 parts by weight of the monomer or oligomer of a), 10 to 30 parts by weight of the aqueous binder of d), and the polymerization initiator of b) to 50 parts by weight of water. Examples include 1 to 5 parts by weight of capsules, and 0.5 to 5 parts by weight of the polymerization accelerator of c) are mixed with water to prepare a suspension.

In the present invention, the filler of e) can be further added if necessary, and the filler of e) is used by applying the composition of a) to d) to a bolt or the like. In this case, the microcapsules containing the polymerization initiator of b) are appropriately compounded so as to be easily broken at the time of fastening the bolts for the purpose of improving the fixing force of the bolts, and the compounding amounts are a) to d. It is preferable to add 1 to 10 parts by weight to 100 parts by weight of the composition (1).

The type and the like of the filler of e) is not particularly limited, but in order to achieve the above-mentioned object, a scale-like shape, a needle-like shape or the like is suitable, and the particle size thereof is the composition described above. To the extent that there is no inconvenience when applying it to bolts, for example 10
It may be 0 μ or less.

Further, in the present invention, a well-known polymerization inhibitor or chelating agent which is well known in the art can be used for imparting stability to the polymerizable monomer or oligomer of a). Specifically, hydroquinone is used as the inhibitor. , Benzoquinone, naphthoquinone, anthraquinone, etc.
-Diketone, ethylenediaminetetraacetic acid, sodium salt of ethylenediaminetetraacetic acid and the like.

Further, in the present invention, plasticizers, pigments, dyes, diluents and the like known in the art are added by any suitable means so long as the objects of the present invention are not impaired. be able to.

[0032]

EXAMPLES The present invention will now be described in detail with reference to examples, but the present invention is not limited thereto. Example 1 a) Component Bisphenol A type epoxy acrylate (BPE-4 manufactured by Shin-Nakamura Chemical Co., Ltd.) 40 parts by weight b) Component Microcapsules in which 50% of diacyl peroxide is included and the wall membrane is composed of melamine-formaldehyde resin 3 Parts by weight c) component dimethyl paratoluidine 2 parts by weight d) component polyvinyl acetal resin (S-REC KW Sekisui Chemical Co., Ltd.) 20 parts by weight The above a) and b) are mixed with 40 parts by weight of water to prepare a suspension. To do. Next, this composition was applied to the thread portion of a zinc-chromate plated bolt (M10 P1.5) and dried at room temperature to obtain a precoated bolt.

Example 2 Component a) Glycidyl methacrylate (Blenmer G manufactured by NOF CORPORATION) 40 parts by weight Component b) 50% of benzoyl peroxide was encapsulated in the wall film of melamine-formaldehyde resin. Part c) Component 3-oxo-2,3-dihydrobenzisothiazole-1,1-dioxide dimethylparatoluidine 2 parts by weight d) Component Polyvinyl acetal resin (ESREC KW Sekisui Chemical Co., Ltd.) 20 parts by weight Above a) to A suspension was prepared by mixing d) with 40 parts by weight of water and stirring. Next, this composition was applied to the thread portion of a zinc-chromate plated bolt (M10 P1.5) and dried at room temperature to obtain a precoated bolt.

Example 3 a) Component 40 parts by weight of bisphenol A type epoxy acrylate (BPE-4) b) Component 3 parts by weight of microcapsules containing 50% of diacyl peroxide and having a wall membrane composed of melamine-formaldehyde resin. c) component dimethyl paratoluidyl 2 parts by weight d) component polyvinyl acetal resin (S-REC KW Sekisui Chemical Co., Ltd.) 20 parts by weight e) component scale-like filler (Mistrovapor Japan Mistron) 5 parts by weight Above a) to e) was mixed with 40 parts by weight of water and stirred to prepare a suspension. Next, this composition was applied to the thread portion of a zinc-chromate plated bolt (M10 P1.5) and dried at room temperature to obtain a precoated bolt.

Comparative Example 1 An ethylene-maleic anhydride linear copolymer (manufactured by Monsanto) was used in place of the polyvinyl acetal resin which was the component d) of Example 1, and other components were the same as in Example 1. A suspension was prepared. Next, this composition was applied to the threads of a zinc-chromate plated bolt (M10 P1.5),
It was dried at room temperature to obtain a precoated bolt.

Confirmation of residue: When the nut was assembled to the pre-coated bolt in the above-mentioned torque test, it was confirmed whether or not the coating film applied to the bolt was scraped off to generate residue.

Torque test: A nut was attached to the pre-coated bolt obtained by the above-mentioned method, tightened at 300 Kgf · cm, then left for 6 hours, and the torque when loosened was measured. The results are shown in Table 1 below.

[0038]

[Table 1]

As is clear from Table 1, in Examples 1 to 3 of the present invention, a stable fixing force without variation was shown even after 6 hours compared with Comparative Example 1, and drying after coating was quick, The mass production is excellent, the generation of scraps at the time of tightening is small, and the breaking torque can be improved by adding the filler as seen in Example 3.

[0040]

In summary, according to the present invention, by using the polyvinyl acetal resin having the above structural formula as the aqueous binder, the monomer or oligomer of a) and the polymerization accelerator of c) or the microcapsules of b) are aqueous. A loose-locking precoated threaded member can be obtained which can be dispersed in the binder in a stable suspension over a long period of time and thus can be stored for a long time.

Claims (17)

[Claims] 1. A precoat type adhesive composition for preventing loosening of a screw member, comprising: a) a monomer or oligomer having a polymerizable double bond at a terminal of a molecule; b) a microcapsule containing a polymerization initiator; c) a polymerization accelerator. d) Aqueous binder represented by the following formula: (In the formula, R is an alkyl group having 1 to 4 carbon atoms, l is 1 to 15, m +
n = 85-99) is contained, The adhesive composition for the loosening prevention of the screw member characterized by the above-mentioned. 2. The weight ratio of the monomer or oligomer having a polymerizable double bond at the end of the molecule of a) to water is 1.
The adhesive composition for locking a screw member according to claim 1, which has a solubility of 0% or less. 3. The screw according to claim 2, wherein the monomer or oligomer having a polymerizable double bond at the terminal of the molecule of a) is a bisphenol A type (meth) acrylate and glycidyl (meth) acrylate. An adhesive composition for preventing loosening of a member. 4. The wall film of the microcapsules encapsulating the polymerization initiator of b) has water resistance.
An adhesive composition for preventing loosening of a screw member according to the item. 5. The adhesive composition for preventing loosening of a screw member according to claim 4, wherein the wall film of the microcapsule encapsulating the polymerization initiator of b) is a melamine resin. 6. The adhesive composition for preventing loosening of a screw member according to claim 1, wherein the polymerization initiator contained in the microcapsule of b) is diacyl peroxide. 7. The adhesive composition for preventing loosening of screw members according to claim 1, wherein the polymerization accelerator of c) is a tertiary amine. 8. The adhesive composition for preventing loosening of a screw member according to claim 7, wherein the polymerization accelerator of c) is dimethylparatoluidine. 9. A precoat adhesive composition for preventing loosening of a screw member, comprising: a) a monomer or oligomer having a polymerizable double bond at a terminal of a molecule; b) microcapsules containing a polymerization initiator; c) a polymerization accelerator. d) Aqueous binder represented by the following formula: wherein R is an alkyl group having 1 to 4 carbon atoms, and 1 is 1
15, m + n = 85 to 99) e) An adhesive composition for preventing loosening of screw members, which comprises a filler. 10. The screw member according to claim 9, wherein the monomer or oligomer having a polymerizable double bond at the terminal of the molecule of a) has a solubility in water of 10% or less by weight. An adhesive composition for preventing loosening. 11. The monomer or oligomer having a polymerizable double bond at the end of the molecule of a) is bisphenol A.
The adhesive composition for preventing loosening of a screw member according to claim 9, which is a type (meth) acrylate and glycidyl (meth) acrylate. 12. The adhesive composition for preventing loosening of a screw member according to claim 9, wherein the wall film of the microcapsule encapsulating the polymerization initiator of b) has water resistance. 13. The adhesive composition for preventing loosening of a screw member according to claim 12, wherein the wall film of the microcapsule encapsulating the polymerization initiator of b) is a melamine resin. 14. The adhesive composition for preventing loosening of a screw member according to claim 9, wherein the polymerization initiator contained in the microcapsule of b) is diacyl peroxide. 15. The adhesive composition for preventing loosening of a screw member according to claim 9, wherein the polymerization accelerator of c) is a tertiary amine. 16. The adhesive composition for preventing loosening of a screw member according to claim 15, wherein the polymerization accelerator of c) is dimethylparatoluidine. 17. The adhesive composition for locking a screw member according to claim 9, wherein the shape of the filler of e) is scale-like.