JP2010138340A - Adhesive, and screw member and nut member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive more excellent in preservation stability in comparison with a conventional microcapsule-type adhesive. <P>SOLUTION: This adhesive contains a first microcapsule involving a polymerizable monomer and a second microcapsule involving a polymerization initiator for polymerizing the polymerizable monomer. Provided are also a screw member in which the surface of a screw thread is coated with the adhesive and a nut member in which the surface of a screw groove is coated with the adhesive. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a microencapsulated adhesive, and more specifically, it is applied to the surface of a thread of a screw member such as a screw or bolt or the surface of a thread groove of a nut member to prevent loosening or adhesion when the nut member is tightened. It is related with the adhesive agent for aiming at provision of.

  An adhesive is applied to the thread surface of a screw member such as a screw or a bolt or the thread groove surface of a nut member to prevent loosening when the nut member is tightened. In addition, the microcapsulated adhesive is applied in advance to the surface of the screw thread or the thread groove, and when the nut member is tightened, the outer shell of the microcapsule is broken by the tightening pressure to develop the adhesive force. There are also known pre-coated screw members and nut members (see, for example, Patent Documents 1 and 2). This pre-coated screw member or nut member has the advantage of excellent storage stability because the microcapsule coated on the thread surface or thread groove surface does not break and does not develop adhesive force until the nut member is tightened. is there.

JP-A-2-308776 Japanese Patent Laid-Open No. 7-331187

  However, the conventional microcapsule type adhesive is a combination of a microcapsule containing a polymerization initiator and a solvent or binder containing a polymerizable monomer that is polymerized by the polymerization initiator. Even if the initiator is protected by the outer shell of the microcapsule, the polymerizable monomer may be deteriorated by heat or light. For this reason, the polymerization of the polymerizable monomer does not proceed sufficiently at the time of tightening the nut, and there is a possibility that the intended adhesive performance will not be exhibited.

  Therefore, an object of the present invention is to provide an adhesive that is more excellent in storage stability than conventional microcapsule adhesives.

In order to achieve the above object, the present invention provides the following adhesive, screw member and nut member.
(1) An adhesive comprising a first microcapsule encapsulating a polymerizable monomer and a second microcapsule encapsulating a polymerization initiator for polymerizing the polymerizable monomer.
(2) The adhesive according to (1) above, wherein the outer shell of the microcapsule is made of polystyrene.
(3) A screw member, wherein the adhesive according to (1) or (2) is coated on a thread surface.
(4) A nut member, wherein the adhesive according to (1) or (2) is coated on the surface of a thread groove.

  In the adhesive of the present invention, since the polymerizable monomer and the polymerization initiator are separately microencapsulated, both the polymerizable monomer and the polymerization initiator are protected by the outer shell of the microcapsule, and only one of them is protected. Excellent storage stability compared to microencapsulated case. Therefore, the screw member and the nut member of the present invention are also excellent in storage stability.

  Hereinafter, the present invention will be described in detail.

  The adhesive of the present invention is obtained by dispersing microcapsules encapsulating a polymerizable monomer and microcapsules encapsulating a polymerization initiator of the polymerizable monomer in a suitable binder.

  The outer shell of the microcapsule is not limited, but polystyrene is preferred because it has high resistance to heat and light and is excellent in storage stability, and the film strength can be varied depending on the degree of polymerization.

  There is no restriction on the combination of the polymerizable monomer and the polymerization initiator, and the combination of various polymerizable monomers conventionally used in two-component mixed type adhesives and the polymerization initiator that cures the polymerizable monomer. can do. Among these, an epoxy resin system, an acrylic resin system, a urethane resin system, and a silicone resin system are preferable, and an epoxy resin system and an acrylic resin system are more preferable in terms of reactivity, physical properties of a cured product, and the like.

  Examples of epoxy resin-based polymerizable monomers include bisphenol type epoxy resins such as bisphenol A type, bisphenol F type, and bisphenol S type, glycidyl ester type epoxy resins, novolac type epoxy resins, cyclic aliphatic epoxy resins, and polyalkylene glycol types. An epoxy resin etc. are mentioned.

  Examples of polymerization initiators to be combined with these epoxy resin polymerizable monomers include, for example, chain aliphatic polyamines, cycloaliphatic polyamines, aliphatic aromatic amines, aromatic amines, modified amines such as amine adducts, polyamide resins, imidazoles, Examples include mercaptans and acid anhydrides, and these can be used alone or in combination of two or more.

  On the other hand, examples of the acrylic resin-based polymerizable monomer include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and glycidyl (meth) ) Acrylate, benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isobornyl (meth) acrylate, dimethylamino (meth) acrylate, diethylamino (meth) acrylic Rate, lauryl (meth) acrylate, cyclohexyl (meth) acrylate, polyethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate , Neopentyl glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, 2,2-bis (4- (meth) acryloxy-diethoxy) phenyl) propane, trimethylolpropane Monomer components such as tri (meth) acrylate, tetramethylolpropane tetra (meth) acrylate, tetramethylolmethane tri (meth) acrylate, polyether-modified urethane (meth) acrylate, polyester-modified urethane (meth) acrylate, polybutadiene-modified (meta ), Oligomer components such as polybutadiene-modified urethane (meth) acrylate, polycarbonate-modified urethane (meth) acrylate, epoxy (meth) acrylate, etc. It is.

  Examples of polymerization initiators combined with these acrylic resin-based polymerizable monomers include hydroperoxide, alkyl peroxide, diacyl peroxide, and ketone peroxide, and more specifically cumene hydroperoxide and t-butyl hydroperoxide. Organic peroxidation such as oxide, permentane hydroperoxide, methyl ethyl ketone peroxide, cyclohexanone peroxide, dicumyl peroxide, benzoyl peroxide, 3,3 ′, 4,4′-tetra (t-butylperoxycarbonyl) benzophenone Things.

  The above-described microcapsules of polymerizable monomers can be used in combination of a plurality of types. In that case, it is necessary to use a corresponding polymerization initiator for each polymerizable monomer.

  In addition to the polymerizable monomer and the polymerization initiator, an activator for activating the reaction can be added to any of the microcapsules. Examples of the activator include amines such as triethylamine, tripropylamine, triallylamine and ethylenediethanolamine, thiourea derivatives such as ethylenethiourea, monobenzoylthiourea and tetramethylthiourea, N, N-dimethylaniline, N, N- Aniline derivatives such as diethylaniline, toluidine derivatives such as N, N-dimethyl-P-toluidine, N, N-diethyl-P-toluidine, L-ascorbic acid, organometallic salts, saccharin mercaptan compounds, etc. It can be used alone or in combination of two or more.

  It is not limited to the method of microencapsulation, For example, well-known methods, such as a coacervation method and an interfacial polymerization method, are employable. Moreover, although it is not limited to the particle size of a microcapsule, several dozen micrometer-several hundred micrometer is suitable.

  The binder is not limited, but, for example, it can exhibit high adhesion to an adherend surface such as the surface of a screw thread or screw groove, and it is easy to generate a suspension. Sodium resin, polyvinyl alcohol, water-soluble polyacetal resin and the like are preferable.

  The present invention also relates to a screw member in which the above adhesive is applied to a thread surface and a nut member in which the above adhesive is applied to a screw groove surface. In addition, there is no restriction | limiting in the screw member and nut member before apply | coating an adhesive agent, and there is no restriction | limiting also in the coating amount of an adhesive agent. The adhesive may be applied to the screw thread or the groove immediately before the screw member and the net member are screwed together, or may be applied to the screw thread or the screw groove in advance. From the viewpoint of workability, it is preferable that the pre-coating type is applied in advance. Since the polymerizable monomer and the polymerization initiator are encapsulated in separate microcapsules, the adhesive of the present invention does not exhibit an adhesive action until the screw member and the nut member are tightened, and is excellent in storage stability.

  Further, the screw member and the nut member may both be coated with an adhesive, but either one may be coated with an adhesive.

  Examples The present invention will be further described below with reference to examples and comparative examples, but the present invention is not limited thereby.

Example 1
A first microcapsule encapsulating an epoxy acrylate, which is a polymerizable monomer, in a shell made of polystyrene was prepared by emulsion polymerization. Moreover, the 2nd microcapsule which encloses the diacyl peroxide which is a polymerization initiator in the outline which consists of polystyrene was prepared by carrying out emulsion polymerization. Then, the first microcapsule is mixed with an aqueous solvent in which the capsule is not dissolved so that the second microcapsule is 30% by mass of the entire coating liquid and the second microcapsule is 30% by mass of the entire coating liquid. Was prepared. And the coating liquid was apply | coated to the thread surface, and the screw member was produced.

(Example 2)
A first microcapsule in which glycidyl methacrylate, which is a polymerizable monomer, was encapsulated in an outer shell made of polystyrene was prepared by emulsion polymerization. Moreover, the 2nd microcapsule which encapsulates the benzoyl peroxide which is a polymerization initiator in the outline which consists of polystyrene was prepared by emulsion polymerization. Then, the first microcapsule is mixed with an aqueous solvent in which the capsule does not dissolve so that the second microcapsule is 30% by mass of the entire coating liquid and the second microcapsule is 30% by mass of the entire coating liquid. Was prepared. Then, the same amount of the coating liquid as that of Example 1 was applied to the thread surface to produce a screw member.

(Comparative Example 1)
A commercially available epoxy adhesive in which only a polymerization initiator was microencapsulated was applied to the thread surface in the same amount as in Example 1 to prepare a screw member.

(Comparative Example 2)
A screw member not coated with an adhesive was prepared.

(Tightening test)
A nut member to which no adhesive was applied was fastened to each screw member with a force of 300 kgf · cm, and after left for 6 hours, the torque required to loosen the nut member was measured. The test was performed three times and the average was obtained. Moreover, when the nut member was tightened, the presence or absence of the adhesive overflowing from the adhesive coating portion was visually confirmed. The results are shown in Table 1.

  As shown in Table 1, the adhesive of the example consisting of the microcapsules encapsulating the polymerizable monomer according to the present invention and the microcapsules encapsulating the polymerization initiator has strong adhesive force and overflows from the coating part. There is no. On the other hand, in the conventional contact agent, the adhesive force is weak and overflows from the coating part.

Claims (4)

  An adhesive comprising: a first microcapsule encapsulating a polymerizable monomer; and a second microcapsule encapsulating a polymerization initiator for polymerizing the polymerizable monomer.   2. The adhesive according to claim 1, wherein the outer shell of the microcapsule is made of polystyrene.   A screw member, wherein the adhesive according to claim 1 or 2 is coated on a thread surface.   A nut member, wherein the adhesive according to claim 1 or 2 is coated on a surface of a thread groove.