JPH07197014A - Thermally expandable sealant - Google Patents

Abstract

PURPOSE:To obtain a sealant which does not shrink after being expanded. CONSTITUTION:This sealant contains exapnadable vinylidene chloride resin particles or their preexpanded particles. The expandable particles are obtd. by homogeneously incorporating a blowing agent into partially cross-linked vinylidene chloride resin particles and convert, when foamed. into a stable porous structure because of the cross-linking.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a heat-expandable sealing agent.

[0002]

2. Description of the Related Art Sealants are used for glass fastening in the construction field,
It is widely used in industries such as metal curtain walls, PC curtain wall joints, ALC panel joints, concrete / precast concrete joints, slate board joints, and joints around sashes, as well as vehicles, ships, and aircraft.

The main purpose of the sealing agent is to maintain the airtightness and watertightness of the joint portion, and a heat-expandable sealing agent has been proposed for the purpose of enhancing the sealing property during construction and fire. As a concrete example, in order to obtain a good sealing effect by injecting a sealing agent into every corner during construction,
JP-A-49-32950 and the like contain an inorganic material such as sodium bicarbonate and organic material such as azohexahydrobenzonitrile to give a foaming property, and JP-A-55-92779 contains a foaming agent. A heat-expandable sealing agent containing a thermoplastic resin microcapsule has been proposed.

Further, as disclosed in Japanese Patent Laid-Open No. 51-151746, in order to prevent the occurrence of a gap in the seam portion sealed by the high heat from the outside, the temperature of the back surface rises and the spread of the fire is prevented. , A fire-proof sealing agent having thermal expansion property has been proposed. Among them, melamine, dicyandiamide, and the like, which have a function of decomposing by heating and releasing gas, are compounded to have foamability.

[0005]

However, those containing a decomposable compound, such as those disclosed in JP-A-49-32950 and JP-A-51-151746, have good foamability but decompose gas. In addition to easy removal and shrinkage, deterioration of foamability due to decomposition of the foaming agent with time is unavoidable. Further, those containing the thermoplastic resin microcapsules having foamability described in JP-A No. 55-92779 and the like are apt to shrink when foamed, so that the function as a foaming sealing agent is insufficient.

[0006]

In view of the problems of these conventional methods, the inventor of the present invention is a heat-expandable sealing agent which can be filled with a sealing agent at every corner during construction to obtain a good sealing effect. In addition, we have found a heat-expandable sealant that can fully function as a fireproof sealant, such as preventing the occurrence of gaps in the seams that have been sealed due to high heat during a fire, and increasing the temperature on the back surface and leading to the spread of fire. ,
The present invention has been completed.

That is, according to the present invention, the partially cross-linked vinylidene chloride resin particles are uniformly contained with a foaming agent to form a foamable vinylidene chloride resin particle or a preliminary thereof, which has a multi-foam structure stabilized by a cross-linking structure during foaming. It is a heat-expandable sealing agent which is characterized by containing expanded particles. The expandable vinylidene chloride resin particles used in the present invention are described in JP-A-63-122745, JP-A-63-122713, JP-A-04-085343 and the like.

The expandable vinylidene chloride resin particles used in the present invention are partially crosslinked amorphous vinylidene chloride copolymer particles in which the entire resin layer is uniformly impregnated with a foaming agent. 10% by weight of amorphous vinylidene chloride copolymer
It is obtained by copolymerizing at least 85% by weight of vinylidene chloride with at least 15% by weight and at most 90% by weight of another monomer. When the content of vinylidene chloride is 10% by weight or less, the strength of the foam is reduced, and when it is 85% by weight or more, it becomes crystalline and it becomes difficult to uniformly impregnate the foaming agent.

Other monomers copolymerizable with vinylidene chloride include vinyl chloride, (meth) acrylonitrile, styrene and its derivatives, (meth) acrylic acid esters such as methyl acrylate and methyl methacrylate, N-phenylmaleimide and the like. N-substituted maleimides and the like can be mentioned. These may be used alone or in combination of two or more.

In order to achieve the object of the present invention, it is necessary that the expandable vinylidene chloride resin particles have a multicellular structure which is stabilized by a crosslinked structure during foaming. When a foaming agent is simply encapsulated, it becomes easy to shrink because it becomes a single cell when foaming. The object of the present invention is achieved only by having a multi-cellular structure and stabilizing by a cross-linked structure.

To form a crosslinked structure, various difunctional monomers such as divinylbenzene and ethylene glycol diacrylate are copolymerized. The degree of crosslinking can be quantified by the ratio (gel fraction) of the insoluble portion of the expandable particles of the vinylidene chloride copolymer such as tetrahydrofuran to the good solvent.
A preferable gel fraction is 20% or more and 90% or less. When the gel fraction is less than 20%, the foam tends to be set after foaming, and the strength of the foam is low. When the gel fraction is 90% or more, the foamability is lowered. As the polymerization method of the vinylidene chloride-based copolymer, known polymerization methods such as suspension polymerization, emulsion polymerization and solution polymerization can be used, but the suspension polymerization in which the polymer is obtained in the form of particles is most preferable.

On the other hand, in order to form a multi-cellular structure, it is necessary that the resin particles contain a foaming agent uniformly. As a method of uniformly containing a foaming agent in the obtained vinylidene chloride resin particles, a direct impregnation method in which the resin particles and the foaming agent are directly contacted in a gaseous or liquid state, or in water in which the foaming agent is added to an aqueous slurry of resin particles There are a suspension impregnation method and a polymerization impregnation method in which a foaming agent is allowed to coexist during polymerization. In order to confirm that the foaming agent is uniformly contained in the resin, the distribution of the foaming agent in the resin can be examined by an infrared spectrophotometer or elemental analysis method.

Examples of the foaming agent include propane, butane,
Hydrocarbons such as pentane and cyclopentane, halogenated hydrocarbons such as methyl chloride and ethyl chloride, HCFCs such as 1,1-dichloro-1-fluoroethane, 1,1,
HFCs such as 1,2-tetrafluoroethane may be mentioned. In the present invention, not only the unfoamed expandable vinylidene chloride resin particles but also 70
It is also possible to use a product which has been pre-foamed at a rate of not more than twice, preferably not more than 60 times. Above 70 times, the foaming ability during heating becomes low. It is also possible to mix a pre-foamed product.

The size of the expandable particles is preferably 0.05 mm or more and 2 mm or less, and the size of the pre-expanded particles is preferably 0.05 mm or more and 8 mm or less.
In the present invention, the expandable vinylidene chloride resin particles or their pre-expanded particles are compounded in the sealing agent. The sealing agent used in the present invention is a silicone resin type, a modified silicone resin type, a polysulfite type, a polyurethane type,
There are elastic type such as acrylic resin type, SBR resin type, acrylic urethane resin type, butyl resin type, rubber asphalt type, etc., and non-elastic type such as glass putty, oily caulking, etc. It

The compounding ratio of the expandable particles to the sealing agent is preferably 60% by weight or less. The blending is determined according to the desired expansion ratio, but if the blending amount of the expandable particles increases, the foaming property increases, but the mechanical strength decreases. The expandable particles and the sealing agent can be mixed with a mixer such as a kneader. The obtained mixture is applied to joints and penetrations of fire walls such as electric wires and cables. In order to obtain a good sealing effect as a heat-expandable sealing agent that can obtain a good sealing effect by injecting a sealing agent into every corner at the time of construction, it is heated using a heating means such as hot air or steam after construction. The heating temperature varies depending on the type of foaming agent used and the softening temperature of the resin, but is preferably 100 to 300 ° C.

[0016]

EXAMPLES The present invention will be specifically described below based on Examples and Comparative Examples.

[0017]

Example 1 100 parts modified silicone resin, 50 parts phthalate ester, 100 parts calcium carbonate, 2 parts hydrogenated castor oil, 1 part antioxidant, 2 parts organosilane, 1 part metal organic acid, 4 parts titanium oxide. After being mixed uniformly, it is composed of 35% by weight of vinylidene chloride, 30% of styrene, 34.95% by weight of acrylonitrile and 0.05% by weight of divinylbenzene, and the proportion of which is insoluble in tetrahydrofuran is 40%.
Then, 20 parts of expandable polyvinylidene chloride resin particles (average particle size 0.7 mm) uniformly containing 10% by weight of n-pentane per resin as a foaming agent were uniformly kneaded to obtain a heat-expandable sealing agent. . 2 mm of the composition on an ALC plate
After being applied at a thickness of 1, the coating was heated with hot air at 180 ° C. for 5 minutes, the thickness of the coating layer increased to 5 mm, and the thickness did not change even when the temperature was restored to room temperature.

[0018]

Example 2 32 parts of acrylic emulsion resin, 1 part of sodium dodecylbenzenesulfonate, 1 part of sodium polymetaphosphate, 7 parts of dioctyl phthalate, 3 parts of polybutene,
After mixing 52 parts of calcium carbonate and 2 parts of titanium dioxide, 50% by weight of vinylidene chloride, 25% of styrene, 24.95% by weight of acrylonitrile, and 0.9% of divinylbenzene.
It is composed of 08% by weight, has a proportion of 60% insoluble in tetrahydrofuran and has a n content of 10% by weight per resin as a foaming agent.
-Fifty parts of expandable polyvinylidene chloride resin particles (average particle size 1.5 mm) containing pentane uniformly were kneaded uniformly to obtain a heat-expandable sealing agent. After the composition was applied on a glass plate in a thickness of 2 mm and then heat-treated with hot air at 250 ° C. for 1 minute, the thickness of the coating layer increased to 4.5 mm, and the thickness changed even when the temperature was restored to room temperature. I didn't.

[0019]

Comparative Example 1 Vinylidene chloride 35% by weight, styrene 30
%, Acrylonitrile 35% by weight, the proportion insoluble in tetrahydrofuran is 0%, and 10% by weight of n-pentane per resin as a foaming agent is uniformly contained in the expandable polyvinylidene chloride resin particles (average particle size). 0.7 mm)
Same as Example 1 except that was used. ALC
After applying a thickness of 2 mm on the plate, apply hot air at 180 ° C for 5
When heat-treated for minutes, it expanded and then contracted, and the thickness of the coating layer increased only to 2.5 mm.

[0020]

[Comparative Example 2] Thermally expandable microspheres (“EXPANCEL-46” manufactured by Nippon Philite Co., Ltd.) containing a foaming agent as an outer shell component of a vinylidene chloride polymer as the expandable resin particles.
1DU ”was used and prepared according to Example 1. After coating the composition on an ALC plate with a thickness of 2 mm,
When heat-treated with hot air at ℃ for 5 minutes, it expanded and contracted, and the thickness of the coating layer increased only to 2.5 mm.

[0021]

[Comparative Example 3] Thermally expandable microspheres (“EXPANCEL-46” manufactured by Nippon Philite Co., Ltd.) containing a foaming agent as an outer shell component of a vinylidene chloride polymer as the expandable resin particles.
1DU ”was used and prepared according to Example 2. After applying the composition onto an ALC plate in a thickness of 2 mm,
When heat-treated with hot air at ℃ for 1 minute, it expanded and then contracted, and the thickness of the coating layer increased only to 2.5 mm.

[0022]

EFFECTS OF THE INVENTION It is possible to provide a heat-expandable sealing agent that does not shrink after expansion. Then, it becomes a heat-expandable sealing agent capable of obtaining a good sealing effect.

Claims (1)

[Claims] 1. A foamable vinylidene chloride-based resin particle or a pre-expanded particle thereof, wherein a foaming agent is uniformly contained in partially crosslinked vinylidene chloride-based resin particles to form a multicellular structure stabilized by a crosslinked structure during foaming. Thermally expandable sealing agent characterized by being blended