JPH03126782A - Cyanoacrylate adhesive composition - Google Patents

Abstract

PURPOSE:To obtain the subject instantaneous adhesive having high normal adhesive strength, small variation of strength during storage, excellent storability and giving a cured resin easily releasable with a solvent such as acetone by adding an OH-containing silicone resin to a cyanoacrylate. CONSTITUTION:The objective instantaneous adhesive giving a cured resin having improved solubility can be produced by adding an OH-containing silicone resin (preferably a resin solid at normal temperature and having a compatibility of >=5% with cyanoacrylate) to a cyanoacrylate.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a novel cyanoacrylate adhesive composition, in particular, which has a high normal adhesive strength, a small change in strength over time during storage, and has excellent storage stability. The latter relates to cyanoacrylate instant adhesives that can be easily peeled off with a solvent such as acetone.

[Conventional technology]

Cyanoacrylate adhesives (hereinafter abbreviated as cyano adhesives) have the property of becoming heavy Br& in a short time due to the moisture adsorbed on the surface of the adherend and the anion activity of the surface itself, and exhibiting strong adhesion. It is widely known as an agent. Taking advantage of this adhesive property, it is used for bonding various materials.

However, recently, in the field of electronic materials and light electric materials, cyano-based adhesives have been used in the field of temporary adhesives, in which the adhesive is subjected to specified processing in the parts processing process, then peeled off and recovered using solvents, and used for parts purposes. The use of drugs is becoming more common.

The above-mentioned cyano adhesive can be used at room temperature for a short time of minutes, for example, in the case of mild steel, the tensile shear strength is 220 to 260 kg/
It has a strength of c/ and strong resistance to various solvents. This adhesive exhibited good adhesion performance except under special conditions such as high temperatures, alkaline conditions, and strong impact peeling, and it was difficult to peel it off quickly without damaging the material.

When it is absolutely necessary to remove the film, methods such as immersion in a solvent such as dimethylformamide, nitromethane, acetone, or hot water for a long time are known.

Therefore, although it is not impossible to use ordinary cyano-based adhesives for temporary fixing purposes, there are problems such as peeling time and deterioration of parts, making it impossible to apply them to production processes.

Various attempts have been made to improve the releasability of cyano adhesives while maintaining their properties, and patents have been proposed. In order to improve the peelability after processing, there are methods using liquid materials such as plasticizers and nitrocellulose, which is easily soluble in various solvents,
A method using an addition condensate of cyanoacetate and formaldevit, which corresponds to a polymer of cyanoacrylate, is known.

Compositions obtained by these methods have good peelability when the adhesive is immersed in acetone, but the adhesive strength under normal conditions is not sufficient.
It has drawbacks such as slow adhesion speed, storage problems, and strong deterioration of strength over time, and improvements have been desired.

Therefore, the present inventors found that the bonding speed and bonding strength showed normal performance, the bonding work was possible, and the subsequent processing work could be carried out without any hindrance. Various studies have been carried out in order to provide a cyano-based adhesive that can be peeled off and parts can be recovered, and is suitable for use as a temporary adhesive in the production of electronic materials, light electrical materials, etc.

As a result, conventionally known compositions exhibit the above-mentioned drawbacks because the additives used for denaturation have low stability or contain impurities that impair the shelf life of the composition. It has also been found that one of the main causes is that the additive is in liquid form, which greatly reduces the physical properties of the cured adhesive. Additives that do not have these drawbacks include those that exhibit good compatibility with cyanoacrylates without impairing stability or hardenability, and those that dissolve quickly in solvents such as acetone and are solid at room temperature. It is necessary that such an additive has Si as a functional group.
It has been found that a silicone resin that is solid at room temperature and has only -OH groups is particularly preferable, leading to the present invention.

[Structure of the invention]

Thus, the present invention provides a cyanoacrylate adhesive that has improved solubility after curing by adding an OH group-containing silicone resin to cyanoacrylate. As the OH group-containing silicone resin, it is preferable to use one that is solid at room temperature and has a compatibility with cyanoacrylate of 5% or more.

[Detailed description of the invention]

The present invention will be explained in detail.

The OH group-containing silicone resin used in the present invention can be dimethylpolysiloxane-based or phenylpolysiloxane-based. The molecular weight of this silicone resin is not particularly limited as long as it has solubility in cyanoacrylate, and the same applies to the skeleton structure. In addition, unless the stability and compatibility of cyanoacrylates are reduced, halogens and acrylics,
There is no problem even if there is a substituent such as methacrylic.

In practice, it can be easily selected from commercially available resins.

An example of a commercially available resin is KR-216 (Shin-Etsu Chemical)
, 5H6018 ()-Resilicon Co., Ltd.).

Even though silicone resin has the same 5iOH group, liquid silicone oil, which is used as the base of room-temperature-transformable rubber, is not compatible with the liquid silicone oil and has disadvantages such as not being able to obtain a stable composition and slow curing speed, so it is preferable. do not have. Although the reason for this is not clear, it is thought that it is related to the fact that the silicic acid properties of the S i -OH group are strong in liquid materials and the structure of the skeleton.

As the cyanoacrylate, various cyanoacrylates that have been conventionally used in instant adhesives can be widely used. More specifically, N HC-C-C0OR (1) (wherein R
represents a straight-chain or branched alkyl group having 1 to 8 carbon atoms, an allyl group, or a phenyl group with or without a substituent. ) can be used alone or in combination of two or more. The alkyl group in this formula (1) can be used in the same way even if it is substituted with a halogen or alkoxy group.

When preparing compositions of the invention using this cyanoacrylate, - stabilizers, as implemented within the shell;
Plasticizers, thickeners, colorants, curing speed regulators, fragrances, etc.
For example, additives such as sulfur dioxide gas, hydroquinone, and phthalic acid dioctyl ester can be selected and added as necessary.

The composition of the present invention can be obtained by adjusting the amount of silicone resin that is solid at room temperature having a 5tOH group in the cyanoacrylate depending on the desired solubility. The solubility of the cured product increases as the amount of silicone resin increases, so the amount added can be determined depending on the desired solubility. Therefore, the amount added is not particularly limited. If less than 2 parts per 100 parts (WT) of cyanoacrylate, the effect of improving solubility will be small, so it is usually more than 2 parts, and if more than 70 parts is added, the curing speed and adhesive strength will decrease, so less than 70 parts,
The amount is preferably about 3 to 30 parts.

〔Example〕

Examples of the present invention are shown below.

Example-1 0.002 parts of sulfur dioxide gas, 0.06 parts of hydroquinone, and 8 parts of dioctyl phthalate were added and dissolved in 100 parts by weight of ethyl-2-cyanoacrylate. S to this
Solid silicone resin commercial product with i-OH group (KR2
16 (Shin-Etsu Chemical Co., Ltd.) was added thereto and dissolved by stirring at room temperature to obtain a colorless solution. The viscosity of the resulting composition was 30c
It was p. It had a viscosity of 35 cp after 4 months storage at room temperature.

Adhesive Performance Measurement Conditions The adhesive performance of this composition was measured according to J I 5K6861.

Measurement results: Mild steel: 14-18 seconds Tensile shear strength: Mild steel: 225 kg/cd Storage stability: Near 0°C, good peeling performance for 5 days without change Measurement conditions: One drop of the sample is placed on a slide glass. An overcoat of cyanoacrylate curing accelerator is applied to this to harden the sample into a lens shape. This is allowed to stand and cure at room temperature for 24 hours. After 24 hours, the sample is immersed in acetone and the solubility is measured by measuring the time until the cured product dissolves and disappears.

Measurement results This composition 14-15 minutes Comparative example 95-100 minutes Comparative example is commercially available from Matsumoto Pharmaceutical Industries Co., Ltd.
A cyano adhesive with a screw strength of 18M having the same composition as in Example 1 was used except that it did not contain an OH group-containing silicone resin.

Example-2 100 parts of ethyl-2-cyanoacrylate, 0.002 parts of sulfur dioxide gas, 0.06 parts of hydroquinone, 10 parts of trioctyl trimellitate, an appropriate amount of a curing accelerator, and a solid silicone resin having 5i-OH groups. Commercially available product (SH6
018 (Toray Silicone Co., Ltd.) was added and stirred to dissolve it to obtain a colorless solution. The viscosity was 38 cp.

The adhesive performance and solubility were measured in the same manner as in Example-1, and the results were as follows.

Adhesive performance set time: PVC resin 14-18 seconds, mild steel 16 seconds
~20 seconds Tensile shear strength: 230 kg/cd Storage stability = 70°C 5 days without change Good dissolution performance This composition 12 to 14 minutes [Effects of the invention] The adhesive composition of the present invention has good fast curing properties. It is an adhesive that exhibits strong contact activity, and the adhesion work can be performed in the same way as general instant contact agents. The present composition is suitable for use in industrial optics, in particular as temporary adhesion for electronic materials, optical materials, light electrical components, etc., which are temporarily bonded and processed, then peeled off and the components are recovered and used for their original purpose. Compositions conventionally proposed for this type of use had problems with peelability, strength, speed, storage stability, etc. and were unsatisfactory, but the present invention does not have these drawbacks and has a balance between peelability and adhesive performance. The present invention provides a new cyano-based adhesive composition, which is extremely useful in the field of parts processing.

Claims (1)

[Claims] 1. A cyanoacrylate adhesive composition obtained by adding an OH group-containing silicone resin to cyanoacrylate to improve solubility after curing. 2. The adhesive composition according to claim 1, wherein the OH group-containing silicone resin is solid at room temperature and has a compatibility with cyanoacrylate of 5% or more.