JPH11310682A - Moisture hardening composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a moisture hardening composition capable of exhibiting excellent performance as an adhesive and a fixer for assembling or the like of an electric product or a precision machine to which fire retardancy is required. SOLUTION: This composition is obtained by compounding (A) 100 pts.wt. of a copolymer having reactive silicon group which can perform crosslinking by hydrolysis and consisting of (1) an acrylic acid alkyl ester monomer unit and/or methacrylic acid alkyl ester monomer unit whose molecular chain is substantially a 1-8C alkyl group and (2) an acrylic acid alkyl ester monomer unit and/or methacrylic acid alkyl ester monomer unit having 10 or more carbon atoms with (B) 50-350 pts.wt. of metal hydroxide having an average particle diameter of 0.1-200 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moisture-curable composition having excellent performance as an adhesive or a fixing agent for assembling electric products or precision equipment requiring flame retardancy.

[0002]

Related Art In general, phosphorus-based flame retardants, halogen-based flame retardants, metal hydroxides and the like are used as flame retardants in flame-retardant adhesives. Among them, polyphosphates such as sodium polyphosphate and ammonium polyphosphate and phosphorus-based flame retardants such as phosphorus pentoxide have a possibility of reducing water resistance and corroding copper.

[0003] Further, it has been pointed out that halogen-based flame retardants represented by brominated flame retardants such as decabromodiphenyl ether and tetrabromobisphenol A have a possibility of causing metal corrosion and air pollution. Although the halogen-based flame retardant greatly improves the flame-retardant effect when used in combination with antimony oxide, there is also a problem that antimony oxide is undesirable because it has toxicity.

On the other hand, aluminum hydroxide and magnesium hydroxide, which are metal hydroxides, have recently been used as non-halogen flame retardants and as flame retardants for various plastics.

[0005] However, when these metal hydroxides are applied to flame retardation of a silyl group-modified polyether type composition, at least 350 parts by weight per 100 parts by weight of the composition is required.
UL94V-0 (sample thickness 1.5
mm) did not exhibit considerable flame retardancy, had poor adhesion to various plastics, and had low heat aging properties.

[0006] The flame retardant regulation of home electric appliances is U.S.
The L standard is the basis, and many products are subject to regulation. Here, UL (Underwriters laboratories I
nc .: Insurer Laboratory) establishes and tests standards for materials, equipment, products, equipment, structures, and methods.
The UL94 standard evaluates the flame retardancy in electrical products and plastic materials, among which UL94V-
0 is defined as the class with the highest flame retardancy.

For use in electrical products, heat resistance around 110 ° C. and about 500 hours or more is required around high-pressure components. However, silyl group-modified polyether-type compositions are significantly deteriorated under the above-mentioned heating conditions, and are sometimes ashed. There was also a problem that it became a state.

[0008]

DISCLOSURE OF THE INVENTION The present inventors have made intensive studies to produce a novel moisture-curable composition having flame retardancy, and found that a (meth) acrylic ester having a reactive silicon group has been obtained. The copolymer has excellent heat resistance as compared to a polyoxyalkylene polymer having a reactive silicon group,
It has been found that even when the cured product is burned, remarkable liquefaction (depolymerization) unlike the oxyalkylene polymer is not observed.

Therefore, the present inventors have satisfies the basic properties as an adhesive and a fixing agent by combining a metal oxide with the (meth) acrylic acid ester polymer having a silicon group. −0 (sample thickness 1.
It has been found that a cured product having flame retardancy that can pass 5 mm) can be obtained, and the present invention has been completed.

An object of the present invention is to provide a moisture-curable composition having excellent performance as an adhesive or a fixing agent for assembling electric products or precision equipment requiring flame retardancy.

[0011]

In order to solve the above-mentioned problems, the moisture-curable composition of the present invention has (a) a reactive silicon group which can be cross-linked by hydrolysis, and (1) the molecular chain has An acrylic acid alkyl ester monomer unit and / or a methacrylic acid alkyl ester monomer unit substantially having an alkyl group having 1 to 8 carbon atoms; and (2) an acrylic acid alkyl ester monomer unit having 10 or more carbon atoms And / or 100 parts by weight of a copolymer composed of methacrylic acid alkyl ester monomer units, and (b) an average particle diameter of 0.1 to 200 μm
And 50 to 350 parts by weight of a metal hydroxide.

The reactive silicon group used in the present invention is a silicon-containing functional group which can be crosslinked by forming a siloxane bond, and can be represented by the following formula (I).

[0013]

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(Wherein, R ¹ is a substituted or unsubstituted monovalent organic group having 1 to 20 carbon atoms or a triorganosiloxy group, X is a hydroxyl group or a different or similar hydrolyzable group, and a is 0,1 Or an integer of 2, b is an integer of 0, 1, 2, or 3, and a = 2 and b = 3, and m is 0 to 1.
An integer of 8. )

As the above metal hydroxide, aluminum hydroxide and / or magnesium hydroxide are preferably used. Aluminum hydroxide, magnesium hydroxide or a mixture thereof has a melting point of about 180 corresponding to the decomposition temperature of the polymer material.
Since the structure water is released at a temperature of up to 320 ° C., it is possible to prevent the ignition of a flame and the spread of fire, and it is possible to exhibit excellent flame retardancy.

The metal hydroxide has a particle size of 0.1 μm to 2 μm.
Although 00 μm is used, 0.3 μm to 100 μm is more preferable, and 0.3 μm to 30 μm is most preferable.

When the particle size of the metal hydroxide is smaller than 0.1 μm, there is a problem that the viscosity of the composition becomes remarkably high and workability is deteriorated. And clogging at the device fitting portion.

The amount of the metal hydroxide is from 50 to 350 parts by weight, preferably from 80 to 280 parts by weight, more preferably from 110 to 230 parts by weight. If the amount of the metal hydroxide is less than 50 parts by weight, sufficient flame retardancy cannot be obtained. For example, when ignited, the flame spread may continue or the polymer may be depolymerized and liquefied. If the amount is too large, the viscosity of the composition increases and the workability deteriorates, and the basic physical properties such as adhesive strength cannot be maintained.

As the metal hydroxide used as a flame retardant, those which are surface-treated with a silane coupling agent, an organic titanate or the like are commercially available. In the present invention, these surface-treated metal hydroxides are used. It can also be used. Further, an inorganic filler such as calcium carbonate can be used in combination with the above-mentioned metal hydroxide. Further, the above metal hydroxide and calcium oxide, magnesium oxide,
When a metal hydroxide such as tin oxide is used in combination, the flame retardancy may be improved.

The above-mentioned flame retardants such as halogen-based, phosphorus-based, and antimony oxide have the above-mentioned problems in ordinary use, but in the present invention, these flame retardants may be used in combination with a metal hydroxide. It is possible. In addition, zinc borate, zinc stannate, and the like can also be added because they have an effect of reducing the amount of smoke generated.

(C) A polymer having a reactive silicon group crosslinkable by hydrolysis and having a molecular chain substantially composed of an oxyalkylene monomer is used for 100 parts by weight of the copolymer. It is preferable to use 10 to 200 parts by weight together.

The (meth) acrylate copolymer (a) having a reactive silicon group has a degree of polymerization of 3000 to 60.
Since the viscosity is high at about 00, the workability may be poor unless diluted with a liquid such as a solvent.

On the other hand, the oxyalkylene polymer (C) having a reactive silicon group has the same degree of polymerization and a lower viscosity than the (meth) acrylic acid copolymer. Therefore, for the purpose of improving workability such as applicability, it is possible to constitute a solvent-free flame-retardant composition by using an oxyalkylene polymer (c) in combination with the copolymer (a). it can.

Further, when an epoxy resin is further used in combination with the composition of the present invention, the residual carbon ratio is improved and the drip property (dropping during combustion) is improved, so that the amount of the metal hydroxide can be reduced. .

Silicone compounds commercially available as flame retardants can be used as non-halogen flame retardant aids.

The bonding method of the present invention is to bond parts of a flame-retardant product using the above-mentioned moisture-curable composition. Flame retardant products include electrical products such as speakers, video cassette players, televisions, radios, vending machines,
Examples include refrigerators, personal computers, card-type batteries, video cameras, cameras and other automobile parts and precision equipment.

In addition to the above, the bonding method of the present invention can also be applied to bonding of high-voltage components, circuits which can be high-voltage and components used in the vicinity thereof, and bonding in electric appliances which are continuously operated for a long time. it can. Specific examples of these components include connectors, switches, relays, electric cables, flyback transformers, deflection yokes, and the like.

[0028]

The present invention will be described more specifically with reference to the following examples.

Production Example 1 (Production Method of Synthetic Product A) 63.5 g of butyl acrylate, 38 methyl methacrylate
9 g, 117 g of stearyl methacrylate, TSMA (γ
-Methacryloxypropyldimethoxymethylsilane) 3
0.5 g, AIBN (azobisisobutyronitrile) 1
2.0 g and 255 g of xylene were mixed and stirred to dissolve uniformly. 30 g of this mixture was added to a 20
The mixture was placed in a 0 ml four-necked flask and heated to 80 ° C. in an oil bath while passing nitrogen gas. After a few minutes, polymerization started and heat was generated. After the heat was calmed, the remaining mixed solution was gradually dropped over 3 hours using a dropping funnel to cause polymerization. The polymerization was terminated when no heat generation was observed. The number average molecular weight was 9,700, the polymerization conversion was 99%, and the resin solid content was 70%.

Production Example 2 (Method for producing compound B) 85.7 g of the compound A synthesized in Production Example 1 and Cyril SA
73.3 g of X350 was placed in a three-necked flask, heated to 80 ° C. in an oil bath while passing nitrogen gas, and the pressure was reduced to remove xylene. Viscosity 100Pa · s at 100% solids
(B-type rotational viscometer, BH-type No. 7 rotor, 20 rpm
m).

(Examples 1 to 3 and Comparative Examples 1 and 2) The components shown in Table 1 (unit: parts by weight) were put in a planetary mixer, mixed at 100 ° C. for 1 hour, and then heated to 20 ° C. After cooling, the curing catalyst and the adhesion-imparting agent were added, and the mixture was vacuum-mixed for 10 minutes under reduced pressure to obtain a room-temperature curable composition for each formulation.

Further, each of the room temperature curable compositions thus obtained was evaluated for flame retardancy and adhesive strength, and the results are shown in Table 1.

[0033]

[Table 1]

Each component in Table 1 is as follows. Silyl MA450: a product of a mixture of a polymer having a main chain of polyoxypropylene and having a dimethoxysilyl group at the molecular terminal and a polymer having a main chain of a copolymer of polymethacrylic acid ester and having a dimethoxysilyl group in the molecule Name (manufactured by Kanegafuchi Chemical Industry Co., Ltd.).

Silyl SAX350: trade name of a polymer having a main chain of polyoxypropylene and having a dimethoxysilyl group at a molecular terminal [manufactured by Kaneka Chemical Industry Co., Ltd.]. Heidilite H21: trade name of aluminum hydroxide (average particle size 25 μm) [Showa Denko KK]. Heidilite H42: trade name of aluminum hydroxide (average particle size 1 μm) [manufactured by Showa Denko KK]. Kisuma 5A (U): Trade name of magnesium hydroxide (average particle size 1 μm) [manufactured by Kyowa Chemical Industry Co., Ltd.] Whiten SB: trade name of calcium carbonate [manufactured by Shiraishi Calcium Co., Ltd.] Dibutyltin dilaurate: curing catalyst SH6020: adhesion-imparting agent [γ- (2-aminoethyl)
Aminopropyltrimethoxysilane] [Toray Dow Corning Silicone Co., Ltd.].

In addition, each performance evaluation in Table 1 was performed as follows.

Adhesive strength (* 2): Mild steel plate (1.6 × 25)
X 100 mm), each adhesive was applied to a thickness of 200 µm with an adhesive area of 25 x 25 mm, and the open time was set to 3 times.
Then, they are bonded at 20 ° C. for 7 days, and the adhesive strength is measured at a pulling speed of 50 mm / min.

Flame retardancy (* 3): A sheet is prepared using an adhesive with a spacer of 1.5 mm between silicone release papers. After 7 days at 20 ° C, peeled off the release paper.
4. In Comparative Examples 1 and 2, a cured sheet of 1.5 × 13 × 130 mm is prepared. In Example 1, after curing with a dryer at 70 ° C. for 7 days, a cured sheet of 1.5 × 13 × 130 mm is prepared. A Bunsen burner having an inner diameter of 9.5 mm is adjusted to a blue flame having a flame height of 19 mm, and an indirect flame is fired for 10 seconds at the center of the lower end of the test piece whose length direction is held vertically by a clamp. As soon as the combustion stops after the flame contact, the flame is again applied to the same portion of the test piece for 10 seconds. Record the first and second burn times.

As is clear from the results in Table 1, Examples 1 to 4 in which a metal hydroxide (aluminum hydroxide) was added,
Comparative Example 1 in which only a conventionally known calcium carbonate was added without adding a metal hydroxide (120 * 1 in the flame-retardant 1st combustion time in Table 1 means that the fuel continued to burn and dropped from the clamp after 120 seconds. ) Is superior in flame retardancy and adhesive strength. In addition, in the case of Comparative Example 2 in which a large amount of metal hydroxide was added, it can be seen that although the flame retardancy can be used, the adhesive strength is greatly reduced.

Next, the case where the moisture-curable composition of the present invention is applied to bonding of a flame-retardant product, for example, a deflection yoke component, will be described with reference to the accompanying drawings.

FIG. 1 is an explanatory perspective view showing the structure of the deflection yoke and the locations where the adhesive is applied. In the figure, reference numeral 10 denotes a deflection yoke having a bobbin 20, and a wedge 22 protruding laterally is provided on a lower surface of the bobbin 20. Reference numeral 24 denotes a coil mounted on the upper surface of the bobbin 20. A ferrite 25 is attached to the coil 24. A mounting plate 2 having a deflection yoke tightening screw 26 is provided on the bobbin.
8, a purity magnet 30, a 4-pole convergence magnet 32 and a 6-pole convergence magnet 34 are stacked and installed.

The assembly of the deflection yoke 10 is performed as follows. After the bobbin 20, the ferrite 25, and the coil 24 are temporarily assembled without using an adhesive, they are bonded to each other with an adhesive. Next, the above magnets 30, 32, 3
4 and parts made of silicon steel plate and parts made of SUS are bonded with an adhesive. Finally, the deflection yoke 10 is temporarily fixed to a cathode ray tube (not shown) using a wedge 22, and then bonded with an adhesive.

That is, the location where the adhesive is applied is the next location as shown in FIG. The side portion 12 on which the purity magnet 30, the 4-pole convergence magnet 32, and the 6-pole convergence magnet 34 are stacked. Joint 14 between deflection yoke tightening screw 26 and mounting plate 28. A joint 16 between the bobbin 20 and the coil 24. Joint 18 between bobbin 20 and wedge 22.

In this case, various adhesives shown in Table 2 are conventionally used as adhesives for bonding the components.

[0045]

[Table 2]

* 1: Polyamide, polyolefin composition. * 2: Chloroprene, nitrile rubber-based composition. * 3: Two-pack type (main resin: epoxy resin, curing agent: polyamine, polyamide, etc.). * 4: One-component deacetoxy room-temperature curing silicone system.

The problems of the conventional adhesive are as follows.

The hot-melt adhesive softens at a high temperature, and may cause a displacement of parts. Since the rubber-based adhesive contains a solvent as a composition, it may cause problems on occupational safety and health, environmental pollution, and may also cause stress cracking by attacking plastic parts.

Silicone RTV has good heat resistance and is solvent-free, but has a problem that its adhesion to various adherends is basically poor.

Since the epoxy adhesive can be cured at room temperature, a two-pack type is usually used. However, measurement errors in the base agent / curing agent, poor yield, and a long curing time when the curing is performed only at room temperature. Was pointed out.

If the moisture-curable composition of the present invention is applied as an adhesive instead of the conventional various adhesives having the above-mentioned problems, the problems of the conventional adhesive can be solved at once. . That is, the moisture-curable composition of the present invention,
It is flame-retardant, solvent-free, does not soften at high temperatures, and has good adhesion to various adherends, so it can be used as an alternative to conventional adhesives. Since it has no problems, it can be used as an ideal adhesive.

[0052]

As described above, the moisture-curable adhesive of the present invention is flame-retardant, easy to use without solvent, does not soften at high temperatures, has good adhesion to various adhesives, and is difficult to cure. This has the effect of being suitably used as an adhesive or fixing agent for assembling electrical products or precision equipment that requires flammability.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a structure of a deflection yoke and a location where an adhesive is applied.

[Explanation of symbols]

10: deflection yoke, 12, 14, 16, 18: adhesive application location.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C09J 171/00 C09J 171/00

Claims (4)

[Claims] (1) an acrylic acid alkyl ester monomer unit having (a) a reactive silicon group capable of being crosslinked by hydrolysis, and (1) a molecular chain having substantially an alkyl group having 1 to 8 carbon atoms; And / or 100 parts by weight of a copolymer comprising (2) an alkyl acrylate monomer unit having 10 or more carbon atoms and / or a methacrylic acid alkyl ester monomer unit;
(B) Metal hydroxide 50 having an average particle size of 0.1 to 200 μm
To 350 parts by weight. 2. The moisture-curable composition according to claim 1, wherein the metal hydroxide is aluminum hydroxide and / or magnesium hydroxide. 3. A polymer having a reactive silicon group crosslinkable by hydrolysis and having a molecular chain substantially composed of an oxyalkylene monomer, relative to 100 parts by weight of the copolymer (a). The moisture-curable composition according to claim 1 or 2, wherein 10 to 200 parts by weight of the coalescing is used. 4. A bonding method comprising bonding a component of a flame-retardant product using the moisture-curable composition according to any one of claims 1 to 3.