JPH06192468A - Near-infrared-curing expandable resin composition and production of composite gasket member using same - Google Patents

Abstract

PURPOSE:To obtain a composition which can give a cured expanded thick product upon irradiation with neat-infrared rays by injecting an inert gas into a composition comprising an addition-polymerizable, ethylenically unsaturated compound and a near-infrared polymerization initiator and foaming the mixture like milk shake. CONSTITUTION:The composition is obtained by injecting an inert gas into a composition comprising an addition-polymerizable, ethylenically unsaturated compound (e.g. acrylate-terminated polybutadiene) and a near-infrared polymerization initiator (e.g. near-infrared-absorbing cationic dye/borate ion complex) and foaming the mixture like milk shake. This composition can give a cured thick product within a short time upon irradiation with near-infrared rays, and therefore a composite gasket member can be produced by applying it on the sealed face of the member in the form of a gasket and curing the applied composition by irradiation with near-infrared rays.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a foamed resin composition capable of obtaining a thick cured product in a short time by irradiation with near infrared rays, and a method for producing a gasket composite member using the same.

[0002]

BACKGROUND OF THE INVENTION Foamed cured products are widely used for applications such as gap filling for the purpose of heat insulation, soundproofing, vibration proofing, weight reduction, casting, coating, gaskets, cushion materials, backup materials and the like.

Conventionally, as a method for producing these expandable cured products, heat-curable resins and rubbers which have been microencapsulated with an organic or inorganic foaming agent and a low boiling point solvent are kneaded and heat-foamed. There is a method of making a foamed cured product.

Further, there is a method in which a mixture of water or the like is added to a urethane resin, and when the urethane resin is cured, the isocyanate groups in the resin are reacted with water to generate carbon dioxide gas to produce a foamed cured product. is there.

Further, there is a method of dehydrogenatively condensing an organosilane having a hydrogen atom directly bonded to a silicon atom in a silicone resin and an organosilane having a hydroxyl group in the presence of a platinum catalyst or the like.

Further, after injecting an inert gas such as nitrogen gas into the hot melt thermoplastic resin under pressure, the hot melt thermoplastic resin is discharged under atmospheric pressure to form a shake-like liquid resin composition having fine bubbles therein. A method of curing to form a foamed cured product has been disclosed (U.S. Pat.
62-87267, 63-264327).

Further, a liquid resin composition in the form of a shake having a fine bubble inside by injecting an inert gas such as nitrogen gas under pressure into a reactive resin such as silicone or urethane with a gear pump or the like and then discharging it under atmospheric pressure. A method of forming a cured product and curing it to form a foamed cured product is commercialized by Nordson.

[0008]

However, the method of obtaining a foam by heat foaming by blending a foaming agent or expandable microcapsules in a thermosetting resin or rubber is generally used for foaming. In general, heating at 100 ° C or higher, preferably at 150 ° C or higher is required, and for heat-curing ones that are cooled and cured, it usually takes tens of minutes to several hours. However, it takes several minutes or more for cooling, and there is a problem that the heat resistance is low.

When the urethane resin is cured, the method of reacting the isocyanate groups in the resin with water to generate carbon dioxide gas to produce a foamed cured product is likewise for a long time of several ten minutes to several hours for curing. Required and the heat resistance of the cured product is low.

The method of obtaining a foamed silicone resin by dehydrogenative condensation of an organosilane has the drawback that the strength of the obtained silicone resin is weak and it is easily torn.

Further, in any of the above-mentioned urethane resin and silicone resin production methods, the rise rate of the reaction is generally too fast, and the foaming and curing reaction proceeds immediately after mixing, so that it is difficult to handle. Since both methods are generally two-component resins, a complicated process of metering and mixing before coating is required, and also troubles such as gelation in the mixing chamber occur.

As for the method of curing a shake-like liquid resin composition obtained by injecting an inert gas into a hot-melt thermoplastic resin under pressure and then discharging it at atmospheric pressure, the heat resistance of the obtained cured product is It has the disadvantage of being poor in nature.

Regarding a method of injecting an inert gas under pressure into a reaction type resin such as silicone or urethane to carry out a curing reaction, since a moisture curing type resin such as silicone or urethane is used, the mixing device must be a closed system. As a result, the cost of the apparatus becomes high, and it takes several days to cure due to moisture curing.

In addition, after an inert gas such as nitrogen gas is pressure-injected into a conventional ultraviolet curable resin on the market by a mechanical means such as a gear pump to form a shake-like liquid resin composition, A method of irradiating ultraviolet rays to cure the resin is also conceivable, but in this case there is a problem that the ultraviolet rays do not pass through the opaque shake-like resin layer, and therefore the resin cannot be cured to the inside in a short time. .

In addition, such an opaque shake-like resin layer does not transmit light having a wavelength shorter than visible light and cannot be blended with a filler or a pigment, and therefore, a siloxane polymer which is particularly required to be reinforced. , Polyether skeleton polymer, polyester skeleton polymer, etc. cannot be reinforced with an arbitrary filler, and therefore, there is a problem that a high-strength, multifunctional, inexpensive compound cannot be freely selected. .

[0016]

In the present invention, therefore, an inert gas is injected under pressure into a composition of an addition-polymerizable ethylenically unsaturated compound and a near-infrared photopolymerization initiator to form a shake-like foam. The present invention proposes a near infrared light curable foamed resin composition.

When the resin composition according to the present invention is made into a shake, it has excellent thixotropy, has a low viscosity, is easy to apply to a work, but has an excellent property that it is difficult to sag. Therefore, by applying this in a gasket shape on the sealing surface of the member and irradiating it with near infrared rays to cure it, a composite member in which the foam gasket is integrated can be efficiently manufactured.

In the present invention, the addition-polymerizable ethylenically unsaturated compound is a monomer having an ethylenically unsaturated group such as vinyl, acryl or methacryl and an oligomer or an ethylenically unsaturated group having a terminal or side chain. All of the polymers can be used.

Particularly, acrylic acid ester or methacrylic acid ester of monohydric alcohol or polyhydric alcohol or 4-
Examples thereof include (meth) acryloyloxyl group-containing aromatic polycarboxylic acids and acid anhydrides thereof, and examples of these esters include 2,2-bis (3-methacryloxy-2-hydroxypropoxy) -phenyl) propane and di (methacryloxy). Ethyl) trimethylhexamethylene diurethane,
2,2-bis (4-methacryloxypolyethoxyphenyl) propane, tetramethyl methane trimethacrylate, tetramethylol methane tetramethacrylate,
Dipentaerythritol hexaacrylate, dipentaerythritol hexamethacrylate, 4- (meth)
There are acryloyloxymethoxy arbonyl phthalic acid and its anhydride, 4- (meth) acryloyloxyethoxycarbonylphthalic acid and its anhydride, and urethane modified products such as epoxy acrylates such as epoxidized soybean oil and epoxidized rosin. Acrylic acid ester of fatty acid-modified alkyd resin, urethane acrylate, urethane methacrylate, epoxy acrylate, epoxy methacrylate, bisphenol A tetraethylene glycol diacrylate, trimethylolpropane tripropoxy triacrylate, tripentaerythritol, acrylic tetrapentaerythritol Acid ester and methacrylic acid ester, acrylate, etc., or polybutadiene, organopolysiloxane having a methacrylate group, etc., Rieteru, polyesters, and the like radical polymerizable liquid rubbers such as acrylate Roni preparative sulfonyl butadiene copolymer.

The near-infrared polymerization initiator used in the present invention includes cyanine dyes and halogenated methyl group-containing triazine compounds or cyanine compounds and metal arene compounds disclosed in JP-A-2-102855. Kaihei 3-11
1402 near-infrared absorbing cationic dye-
A borate anion complex can be used.

Further, cyanine dyes, diphenyliodonium salts and N-phenylglycine introduced in other literatures [Masami Kawabata, Masahiko Harada, Yasuyuki Takimoto, Proceedings of the 79th Autumn Meeting of the Printing Society of Japan P .81 (Osaka, November 1987)], branched polyethyleneimine and methylene blue (special table 60-502
No. 125) can also be used.

These initiators are in the near infrared region 650
Excited by light energy in the region of ~ 1500 nm,
Near-infrared absorbing cationic dye disclosed in 3-111402-
Since the initiator composed of a borate anion complex can be cured in the long wavelength region of 820 to 880 nm, it has a feature of excellent light transmittance.

The compounding amount with the near infrared photopolymerization initiator is usually 100: 100 with respect to the compound having a polymerizable ethylenic double bond.
It can be used in the range of 0.01 to 20% by weight. In this case, if it is less than 0.01% by weight, it will not cure, and if it is more than 20% by weight, it will not be dispersed.

Further, it is desirable to use an autoxidizer capable of absorbing oxygen in the free radical chain process described in JP-A-3-111402 together with the compound having an ethylenic double bond.

Specific examples thereof include N, N, dialkylaniline, and one or more of ortho, meta or para position is an alkyl group, phenyl group, acetyl group, alkoxy group, ethoxycarbonyl group, carbonyl group, carboxylate group, Examples thereof include N, N, -dialkylaniline substituted with silyl group, phenoxy group, acetyloxy group, hydroxy group, halogen group and the like.

In some cases, the curing rate can be improved by using a boron-based sensitizer described in JP-A-4-80204, and a specific example thereof is a quaternary ammonium boron complex, Methyl ammonium n-
Butyl triphenyl boron, tetramethyl ammonium n-butyl trianisyl boron, tetramethyl ammonium n-octyl triphenyl boron, tetramethyl ammonium n-octyl trianisyl boron, tetramethyl ammonium n-butyl triphenyl boron, tetramethyl ammonium n- Butyltrianisylboron,
Examples include trimethylhaloid rogen ammonium n-butyl triphenyl boron, triethyl hydrogen ammonium n-butyl triphenyl boron, and tetramethyl ammonium n-butyl triphenyl boron.

In addition to these, an ultraviolet absorber, an antifungal agent, an adhesion improver, a flame retardant and the like can be freely blended as required.

As the inert gas used in the present invention, basically any gas can be used as long as it does not affect the ethylenically unsaturated compound, for example, nitrogen or hydrogen. , Carbon dioxide, oxygen, argon, helium and the like.

As the gas mixing device which can be used in the present invention, as long as an inert gas can be mechanically injected under pressure into the ethylenically unsaturated compound,
Any of these can be used. Specifically, "Home Melt System Series FM151" is used to pressurize nitrogen gas etc. into hot melt adhesive by a two-stage gear pump commercialized by Nordson. , FM152, FM
153 ”(trade name) and the like, and any other material that can be physically mixed while blowing gas into a dynamics mixer, a twin-screw mixer, an extruder, etc. can be used. .

In order to foam the composition in which the inert gas is injected under pressure in the form of a shake, means for stirring the composition while injecting the inert gas under pressure, or discharging the composition under atmospheric pressure is used. When the shake-like liquid resin composition thus obtained is irradiated with near-infrared rays, it cures to obtain a foamed cured product.

Here, the near infrared light source is 600 nm.
Any light source that emits a wavelength of ~ 1500 nm may be used, and specifically, a halogen lamp, a semiconductor laser,
A light emitting diode can be mentioned.

The near-infrared ray used in the present invention has a very high transparency and is not only used in the opaque shake-like liquid resin composition as described above, but also in a shake-like liquid resin composition containing a filler and the like. It is possible to permeate through the inside and obtain a thick cured product without any problem.

Therefore, when ultraviolet rays are used, the permeability to an opaque, shake-like resin composition is low, and the filler to be blended is limited. However, any filler can be blended in the present invention. .

The type of this filler is fumed silica,
There are calcined silica, precipitated silica, fumed titanium, and those whose surfaces are hydrophobized with organochlorosilanes, polyorganosiloxanes, hexamethylsilazane, etc. Other fillers include calcium carbonate and organic acid surface treatment. Calcium carbonate, diatomaceous earth, ground silica, aluminum silicide, magnesia, alumina, etc.

[0035]

INDUSTRIAL APPLICABILITY Near infrared rays used in the present invention have high transparency, and therefore, even if an opaque shake-like resin composition or a resin composition containing various fillers is irradiated, the near-infrared ray will have a short thickness. A foamed cured product can be obtained.

Further, the resin composition according to the present invention is a solvent-free one-liquid type, and does not cure unless irradiated with light, so that it does not cure inside the nozzle and the handling time can be freely set. In addition, it has excellent thixotropy, and once it is irradiated with near infrared rays, it can be cured in a short period of time, so workability is extremely good.

Further, the near-infrared lamp used in the present invention does not generate harmful gas such as ozone gas unlike a UV lamp, and therefore, there is no need for equipment such as ventilation, and the lamp cost is low and the life is long. This is a great advantage for downtime, productivity improvement, quality improvement or automation.

Further, according to the present invention, a foamed cured product which is lightweight, has high heat insulating properties, high sound insulating properties, high vibration absorption properties, and has high compression recovery properties in the case of an elastomer base is obtained. Casting, coatings and gaskets, cushioning materials, backup materials for filling gaps, more specifically, heat insulating coatings around the refrigerant of heat exchangers, filling, heat insulation of housing wall materials, anti-condensation coatings, automobile bonnets. It can be used for various purposes such as a soundproof coating on the back of the.

Further, according to the present invention, metal, plastic,
A composite material in which a foam gasket is integrated can be efficiently produced by applying a shake-like liquid resin composition in the shape of a gasket on the flange surface of a member made of wood, ceramics, or any other material and irradiating it with near infrared rays. .

Therefore, for example, automobile parts such as a timing belt cover, a canister, an air filter, an electric product such as a hard disk cover, a thermos bottle, a case seal of an electric rice cooker, a camera back, a waterproof telephone, a precision instrument such as a waterproof watch, etc. Also, it can be widely used for water purifiers, air conditioner outdoor unit covers, gas water heaters, etc.

[0041]

EXAMPLES Examples of the present invention will be shown below. The compositions of Examples 1 to 10 and Comparative Example 1 were prepared using the following base resins, and various tests were conducted. Table 1 below shows the compounding components of Examples 1 to 10 and Comparative Example 1 and their compounding ratios. here,

P-1 Prepolymer made into acrylate by modifying both ends of polypropylene glycol having a molecular weight of 3000 with hydroxyl groups at both ends by urethane bond modification P-2 Both ends acrylate polybutadiene, trade name "ACR-"
LC "(manufactured by Idemitsu Petrochemical Co., Ltd.) P-3 Dimethylpolysiloxane having a molecular weight of 18,000 and a methacrylate group at both ends.

The absorption wavelengths and structural formulas of cyanine dye complexes * 1 to * 3 are shown below, and Darocur 11
73 is an ultraviolet irradiation type polymerization catalyst.

[0044]

[Chemical 1]

FIG. 1 shows a foam melt mixer manufactured by Nordson Co. having a two-stage gear pump used as a gas mixing device in this embodiment. In this device, 1 is a gas supply line, 2 is a gas control valve, and 3 is a gas control valve.
Is a tank, 4 is a gear pump chamber, 5 is a drive motor of the gear pump, 6 is a discharge line, 7 is a discharge port, and the molten base polymer in the tank 3 and the additives shown in Table 1 are sequentially pumped to the tank 3 by the gear pump. Is supplied into chamber 4,
Here, an inert gas such as nitrogen gas supplied through the gas supply line 1 is injected under pressure into the molten base polymer, and this melt is discharged through the discharge line 6 into the atmospheric pressure from the port 7. To form a shake-like liquid resin composition.

Various characteristics of Examples 1 to 10 and Comparative Example 1 are shown in Table 1 below. here,

Sagging property: According to JIS A 5758 (sealing material for construction) 5.3 slump test. Using a test jig specified by JIS, leave it still at 25 ° C for 6 hours, and measure the length to the hanging tip.

Curing time: The resin is poured into a Teflon mold frame of 100 × 100 × thickness of 2 mm, irradiated with a halogen lamp with an output of 500 W and a color temperature of 3200 K at an irradiation distance of 100 mm, and the time until curing is measured. To do.

Hardness, tensile strength, elongation: JIS K 6301
(Vulcanized rubber physical test method). Cured thickness: 20mm high glass bottle is filled with resin and output
Irradiate with a 500W halogen lamp at an irradiation distance of 100m for 2 minutes,
Measure the thickness of the cured part. Foaming conditions: Using a foam melt mixer manufactured by Nordson, at normal temperature, nitrogen gas was mixed and discharged at a gas pressure of 4 kg / cm ² . Expansion ratio: original specific gravity of resin / specific gravity of foam after curing Compression set: According to JIS K6301 (vulcanized rubber physical test method). Compression condition, 100 ℃, 72h.

Regarding the adhesiveness, each of the cured products of the foams of the present invention showed good adhesiveness to the aluminum plate.

[0051]

[Table 2]

[Brief description of drawings]

FIG. 1 is a mechanical diagram of a mixer used in this example.

[Explanation of symbols]

 1 Gas Supply Line 2 Gas Control Valve 3 Tank 4 Gear Pump Chamber 5 Gear Pump Drive Motor 6 Discharge Line 7 Discharge Port

[Table 1]

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Claims (2)

[Claims] 1. Near-infrared light curing, characterized in that an inert gas is injected under pressure into a composition of an addition-polymerizable ethylenically unsaturated compound and a near-infrared photopolymerization initiator to form a shake-like foam. Molded resin composition. 2. A gasket is provided on a sealing surface of a member with a resin composition in which an inert gas is injected under pressure into a composition of an addition-polymerizable ethylenically unsaturated compound and a near-infrared photopolymerization initiator to foam in a shake shape. A method for producing a gasket composite member, characterized in that the gasket composite member is applied in a shape and is further irradiated with near infrared rays to be cured.