JP2002088343A - Elastic sealing material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an elastic sealing material of a one-component type acrylic emulsion type, capable of improving elastic recovery without reducing other properties such as elongation. SOLUTION: This elastic sealing material comprises a copolymer composed of (a) 84.5-98.88 wt.% acrylic ester having a 4-12C alkyl group, (b) 1-10 wt.% acrylonitrile and/or methacrylonitrile, (c) 0.1-5 wt.% α,β-unsaturated carboxylic acid, and (d) 0.02-0.5 wt.% ethylenically unsaturated polyfunctional crosslinkable monomer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealing material having elasticity, and more particularly to an acrylic emulsion type elastic sealing material.

[0002]

2. Description of the Related Art Architectural sealing materials are roughly classified into irregular sealing materials and fixed sealing materials. The irregular sealing material includes an inelastic type and an elastic type. This non-elastic type includes glass putty, oily caulking material and asphalt type. The elastic type is divided into one-component type and two-component type depending on the form. , Solvent type and emulsion type. The emulsion type is the same as the solvent type and is a dry-curing type, and is classified into an acrylic type and a styrene butadiene type.

[0003] This acrylic emulsion type elastic sealing material is used for waterproofing ground treatment such as repair of cracks in concrete, ALC boards and blocks, expansion joints, repair of joints and cracks at places subject to vibration, steel structure, ALC It is a sealing material used for repairing joints, water supply, gas, drainage, electricity, and other piping joints, duct joints, and outer wall cracks.

The acrylic emulsion-type elastic sealing material is odorless and easy to handle because it is water-based.

[0005]

However, for use in applications requiring high-performance elasticity resilience, this acrylic emulsion-type elastic sealing material is required to have an elongation at the maximum strength and an elongation at break. It is necessary to improve only the elastic restorability (rubber-like elasticity) without lowering, but this has been difficult. Therefore, for applications requiring high-performance elastic restorability, two-component silicone-based elastic sealing materials, two-component polysulfide-based elastic sealing materials, two-component modified silicone-based elastic sealing materials, one-component silicone-based elastic sealing materials, and the like. Is used. However, all of them use a solvent, so that odor countermeasures are required and handling requires caution.

Accordingly, an object of the present invention is to provide a one-component acrylic emulsion-type elastic sealing material that improves elastic resilience without lowering other physical properties such as elongation.

[0007]

Means for Solving the Problems The inventor of the present invention provides a sealing material comprising (a) 84.5 to 98.88% by weight of an acrylate ester having an alkyl group having 4 to 12 carbon atoms,
(B) 1 to 10% by weight of acrylonitrile and / or methacrylonitrile, (c) α, β-unsaturated carboxylic acid 0.1% by weight.
1 to 5% by weight, and (d) a copolymer of 0.02 to 0.5% by weight of an ethylenically unsaturated polyfunctional crosslinkable monomer, that is, each of the above components (a) to (c) (D)
The present inventors have found that by adding components and copolymerizing, it is possible to exhibit elastic resilience and to maintain other physical properties such as elongation, thereby solving the above problems.

[0008]

Embodiments of the present invention will be described below.

The elastic sealing material according to the present invention comprises:
Component (a) is an acrylate ester having an alkyl group having 4 to 12 carbon atoms, component (b) is acrylonitrile and / or methacrylonitrile, and component (c) is α or β.
-An acrylic emulsion-type elastic sealing material comprising a copolymer containing four components of unsaturated carboxylic acid and (d) an ethylenically unsaturated polyfunctional crosslinking monomer.

Specific examples of the above component (a) include butyl acrylate, amyl acrylate, 2-ethylhexyl acrylate, heptyl acrylate, isooctyl acrylate, n-nonyl acrylate, isononyl acrylate, decyl acrylate and Lauryl acrylate and the like can be mentioned. This component (a) can be used in combination of two or more types, as well as one type described above. The amount of the component (a) used is 84.5 to 9 based on the whole copolymer.
8.88% by weight is preferred, and 89.2 to 96.97% by weight is preferred. Within this range, it is possible to impart elasticity without impairing the properties exhibited by the other copolymer components, which is economically advantageous.

The amount of the component (b) is preferably 1 to 10% by weight, more preferably 2.5 to 7.5% by weight, based on the whole copolymer. If the amount is less than 1% by weight, the elasticity tends to be insufficient, and if it is more than 10% by weight, the sealing material may be too hard.

Specific examples of the component (c) include acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, crotonic acid and fumaric acid. As the component (c), not only one of the above-mentioned components but also a combination of two or more thereof can be used. The amount of the component (c) used is preferably 0.1 to 5% by weight, more preferably 0.5 to 3% by weight, based on the whole copolymer. When the amount is less than 0.1% by weight, the stability of the sealing material is reduced. When the amount is more than 5% by weight, the water resistance may be deteriorated.

Specific examples of the component (d) include divinyl compounds such as divinylbenzene, diallyl phthalate, ethylene glycol dimethacrylate, trimethylolpropane triacrylate, and allyl acrylate; glycidyl group-containing monomers such as glycidyl methacrylate and glycidyl acrylate; There is N-methylol acryl amide and the like, the amount of use thereof, based on the entire copolymer,
The content is preferably 0.02 to 0.5% by weight, and more preferably 0.05 to 0.2% by weight. If it is less than 0.02% by weight, the crosslinking property is low,
The satisfactory elastic restoring effect of the present invention cannot be obtained. On the other hand, if it exceeds 0.5% by weight, the crosslinkability becomes too high and the elongation performance and the like are lowered.

The component (d) is preferably a glycidyl group-containing monomer, more preferably glycidyl methacrylate.

The glass transition temperature of the above copolymer (hereinafter referred to as
Abbreviated as "Tg". ) Is -20 ° C to -80 ° C,
-35 ° C to -70 ° C is preferred. If Tg is higher than −20 ° C., the flexibility becomes insufficient, and the item does not conform to the item of elastic recovery (%) of JIS-A5758 (construction sealing material). In addition, it is difficult for the copolymer Tg to be lower than −80 ° C. because it contains each of the high Tg copolymer components (b), (c) and (d).

The Tg of the above copolymer means a value calculated by the following FOX equation. [Formula of FOX] 1 / Tg = Wa / Tga + Wb / Tg
b + ... (where Tg is the glass transition temperature (K) of the copolymer, Tg
a, Tgb, ... are the glass transition temperatures of the homopolymers of the monomers a, b, ..., Wa, Wb, ...
Represents the weight fraction of monomer a, monomer b,... As the glass transition temperature of the monomer homopolymer used in the above calculation, a value according to the standards of the Japan Emulsion Manufacturers Association can be used. The values are shown in Table 1. In addition, according to Japan Emulsion Industry Association Standards, for copolymer monomers for which the glass transition temperature of the homopolymer cannot be confirmed,
If it is less than 5% by weight, it can be excluded from the calculation.

[0017]

[Table 1]

The weight average molecular weight of the copolymer is 10,000 to
One million is preferred, and 100,000 to 700,000 is preferred. When the weight average molecular weight is less than 10,000, the water resistance is reduced, and the adhesiveness and elongation performance after immersion in water are insufficient. On the other hand, if it is higher than 1,000,000, the flexibility is insufficient, and the elastic recovery (%) of JIS-A5758 (construction sealing material) is not met. The weight average molecular weight can be measured by gel permeation chromatography (GPC) using polystyrene as a standard substance.

The above-mentioned copolymers can be used as the above-mentioned (a) to (d)
Are obtained by emulsion polymerization of the above components. That is, these components are uniformly dispersed in water by the surfactant. Then, a copolymer is obtained by adding a water-soluble persulfate, hydrogen peroxide, α-cumyl hydroperoxide or the like as a polymerization catalyst and polymerizing. In this emulsion polymerization, since water is used as a medium, heat of polymerization can be dispersed to adjust the polymerization reaction. This makes it possible to adjust the Tg and the weight average molecular weight. The obtained copolymer is obtained in an emulsified state (emulsion) dispersed in water.

The above-mentioned elastic sealing material is produced by blending a plasticizer, a dispersant, a lightweight filler, a filler, a drying regulator, an antifreezing agent and the like into the above-mentioned copolymer.

The above-mentioned plasticizer is used for the purpose of softening the above-mentioned copolymer and improving the film-forming property. Examples of the plasticizer include dibutyl phthalate (DBP), dioctyl phthalate (DOP), tricresyl phosphate (TCP) and the like. The amount of the plasticizer is preferably 12 to 35 parts by weight, and more preferably 20 to 28 parts by weight, based on 100 parts by weight of the copolymer. If the amount is less than 12 parts by weight, the flexibility of the sealing material is insufficient, and
If it is more than 35 parts by weight, it tends to be too soft and insufficient elasticity.

The above-mentioned dispersant is used for the purpose of deflocculating and dispersing the filler and reducing the viscosity of the sealing material. Examples of dispersants include low molecular weight ammonium polyacrylate, sodium polyacrylate, and the like. The amount of the dispersant is preferably 0.1 to 5 parts by weight, more preferably 0.5 to 3 parts by weight, based on 100 parts by weight of the copolymer. If it is less than 0.1 part by weight, the dispersion of the filler is poor, and the viscosity stability of the sealing material may be insufficient,
If the amount is more than 5 parts by weight, water resistance may be deteriorated.

The above lightweight filler is used for the purpose of reducing transportation costs and improving workability. Examples include natural lightweight aggregates (volcanic rubble) and hollow fine particles such as microcapsules. The blending amount of this lightweight filler is preferably 5 to 20 parts by weight based on 100 parts by weight of the copolymer.
7-18 parts by weight are preferred. If the amount is less than 5 parts by weight, the effect of lowering the density of the sealing material may be insufficient, and the workability during transportation and handling may be inferior. If the amount is more than 20 parts by weight, the strength of the sealing material tends to decrease. is there.

The above-mentioned filler is used to increase the non-volatile content,
That is, it is used for the purpose of reducing shrinkage during drying and speeding up drying. Examples include calcium carbonate, china clay, talc and the like. The amount of the filler is 75 to 200 parts by weight based on 100 parts by weight of the copolymer.
Parts by weight, preferably 80 to 165 parts by weight,
130 parts by weight is more preferred. If the amount is less than 75 parts by weight, the ratio of the resin component is increased, and the tackiness and stainability of the surface may be deteriorated. If the amount is more than 200 parts by weight, the sealing material may be hardened and elongation may be reduced. is there.

As the drying regulator, a nonionic surfactant such as polyoxyethylene alkyl phenyl ether is used. The amount of the drying regulator is preferably 0.2 to 4 parts by weight based on 100 parts by weight of the copolymer.
0.5 to 3 parts by weight is preferred. If the amount is less than 0.2 parts by weight, the viscosity stability of the sealing material may be insufficient, and if it is more than 4 parts by weight, the water resistance may deteriorate.

The above-mentioned antifreezing agent is used to lower the freezing start temperature. Examples include ethylene glycol and the like. The amount of the antifreeze is preferably 1 to 7 parts by weight based on 100 parts by weight of the copolymer.
1.5 to 5 parts by weight is preferred. If less than 1 part by weight,
In some cases, the effect of preventing freezing is insufficient, and when it is more than 7 parts by weight, the water resistance of the sealing material may be deteriorated.

[0027]

EXAMPLES The invention relating to this elastic sealing material will be described in more detail with reference to examples.

Example 1 [Synthesis of Acrylic Emulsion] In a reactor equipped with a stirrer, a reflux condenser, a thermometer and a dropping funnel, 20.
6 parts by weight and Eliminol ES-70 as a surfactant
(Manufactured by Sanyo Chemical Industry Co., Ltd.), 0.05 parts by weight, 6
The temperature was raised to 8 ° C. Next, 1.7 parts by weight of a 10% aqueous solution of ammonium persulfate was added with stirring.

As the monomer component, acrylic acid 2-
Ethylhexyl (hereinafter abbreviated as "EHA") 88.
4 parts by weight, 5 parts by weight of butyl acrylate (hereinafter abbreviated as "BA"), 5 parts by weight of acrylonitrile (hereinafter abbreviated as "AN"), and acrylic acid (hereinafter abbreviated as "AA"). ) 1.5 parts by weight, 0.1 part by weight of glycidyl methacrylate (hereinafter abbreviated as “GMA”), and 2.7 parts by weight of Eliminol ES-70 (manufactured by Sanyo Chemical Industries, Ltd.) as a surfactant component. Part and Neugen ET-160
(Daiichi Kogyo Seiyaku Co., Ltd.) 2.1 parts by weight of water 44.4
It was emulsified to parts by weight to prepare a monomer emulsion.

The resulting monomer emulsion was continuously dropped into the above reactor over 4 hours using a dropping funnel. During this time, the polymerization temperature was maintained at 72 to 75 ° C,
The aging reaction was performed at 80 ° C. for 3 hours.

After the reaction, the reaction solution was cooled to 30 ° C.
0.63 parts by weight of aqueous ammonia, adecanate B-940
(Asahi Denka Co., Ltd., antifoaming agent) 0.01 part by weight, chloroacetamide (Clariant Japan Co., Ltd., antiseptic and fungicide) 0.46 part by weight, and 60% Nonipol 110 (Sanyo Chemical Industry Co., Ltd.) 30.1 parts by weight), a nonvolatile content of 60.1%, a viscosity of 4650 mPas, a pH of 4.8 and a T
An acrylic emulsion having a g of 62.8 ° C. and a weight average molecular weight (hereinafter, abbreviated as “Mw”) of 232,000 was obtained.

The nonvolatile content, viscosity, pH, Tg and Mw of the obtained acrylic emulsion were measured by the following methods.
Table 1 shows the results.

Non - volatile content JIS-K6833 (Synthetic resin emulsion test method)
1 g of a sample is accurately weighed into a 4 cm-diameter aluminum dish, placed in a drier kept at 105 to 110 ° C., heated for 3 hours, allowed to cool in a desiccator, and weighed after drying the sample. We weighed it.

Viscosity According to JIS-K6833, about 250 g of a sample was placed in a polybeaker, immersed in a water bath at 25 ± 1 ° C. for 1 hour, sufficiently stirred with a glass rod, and rotated at 20 rpm using a B-type rotational viscometer.
m was measured.

[0035] The pH was measured in accordance with the pH JIS-K6833.

Tg was calculated by the above FOX equation. In addition, the glass transition temperature of the homopolymer of the monomer used for the calculation used the value according to the standard of the Japan Emulsion Manufacturers Association shown in Table 1. In addition, according to the standards of the Japan Emulsion Industry Association, copolymer monomers for which the glass transition temperature of the homopolymer could not be confirmed were excluded from the calculation if they were less than 5% by weight.

Gel permeation chromatography using Mw polystyrene as a standard substance (GPC, manufactured by Shimadzu Corporation;
LA-6A).

[Incorporation of elastic sealing material] DOP was added as a plasticizer to 100 parts by weight of the above acrylic emulsion.
25 parts by weight (manufactured by Daihachi Chemical Industry Co., Ltd.), 1 part by weight of low molecular weight ammonium polyacrylate (manufactured by San Nopco; SN Dispersant 5027) as a dispersant, and natural lightweight aggregate (volcanic rubble) as a lightweight filler 17 parts by weight (manufactured by Shiraxu Corporation: PB-02), calcium carbonate (NS-100, manufactured by Nitto Powder Co., Ltd.) 100 as a filler
Parts by weight, 1 part by weight of polyoxyethylene alkylphenyl ether (manufactured by Sanyo Chemical Industries, Ltd .; Nonipol 110) as a drying regulator, and 2 parts by weight of ethylene glycol (manufactured by Mitsubishi Chemical Corporation) as a deicing agent Then, an elastic sealing material was manufactured.

The viscosity of the obtained sealing material was measured using a BH type viscometer (manufactured by Tokimec Co., Ltd.) at a rotor # 7 and a rotation speed of 10 rpm. Table 2 shows the results.
Further, according to the following method, a coating film of a sealing material was produced, and its strong elongation and elastic recovery were measured. Table 3 shows the results.

[Preparation conditions for coating film of sealing material] A polyethylene sheet was stuck on a glass plate, and about 2 mm
Apply each sealant thickly using a trowel, 20 ° C, 6
After curing for 3 days at 0% RH, the polyethylene sheet was peeled off, and the back surface was cured for 4 days under the same curing conditions.
Dry curing was performed at 0 ° C. for 6 days to prepare a coated film sheet of the test piece.

[Measurement conditions of strength and elongation of coating film of sealing material] Each sealing coating film prepared as described above was subjected to dumbbell 2
Each sample was punched with a mark, and a 20-mm mark was provided at the center of each sample, and the sample was used for a high elongation test.

The strength and elongation test was carried out using a universal tensile tester (UTM-5T, manufactured by Toyo Baldwin Co., Ltd.). The elongation and strength between the 20 mm mark lines were measured (the test atmosphere was 26 ° C., 68% RH).

According to the chart, the strength at 50% elongation (hereinafter abbreviated as “M ₅₀ ”) and the elongation at the maximum strength (hereinafter “S ₅₀ ”).
_MAX ”. ), Its strength (hereinafter abbreviated as “T _MAX ”), and elongation at break (hereinafter abbreviated as “Sb”) were confirmed, and the results were measured for strong elongation.

[Evaluation Conditions for Elasticity Restoring Property of Sealing Coating Film] Each sealing coating film prepared as described above was punched out with a dumbbell No. 2, and a 20 mm mark was placed on the center of each sample to give an elasticity. It was used for a pseudo test of resilience.

The pseudo test of the elastic restorability was carried out in the middle of the test.
The length between the marked lines was extended to about 32 mm, and both ends were fixed. After standing at 26 ° C. and 68% RH for 36 hours, the length of the extended lines between the marked lines was measured, and the fixing was removed to remove Teflon (registered trademark). ) Difference between the length between the marked lines after leaving for 1 hour on the plate (hereinafter abbreviated as “restoration rate (1)”) and the difference between the length between the marked lines after leaving for 3 hours (hereinafter, referred to as “recovery rate (1)”). "Restoration ratio (2)") was measured.

(Examples 2 to 7, Comparative Examples 1 to 4) An acrylic emulsion was prepared according to the formulation shown in Table 2, a sealing material was manufactured according to the method described in Example 1, and the high elongation and elastic resilience were obtained. Was measured. Table 3 shows the results.

In Comparative Example 4, a commercially available sealing material was used.

[0048]

[Table 2]

[0049]

[Table 3]

Results M ₅₀ , T _MAX , S _MAX , Sb, restoration rate (1) and restoration rate (2) are compared with Comparative Example 4 (commercially available). Each item (especially the restoration rate (1) and the restoration rate (2)) has a numerical value of Comparative Example 4.
The higher the performance, the better the performance.

In Examples 1, 2, 6 and 7, all items have higher numerical values than Comparative Example 4. Therefore, in these cases, the film properties (including the restoration rate) of the sealing material are excellent.

Example 5 in which the amount of GMA copolymerization was lower than that described above
In FIG. 5, Sb, the restoration rate (1) and the restoration rate (2) are higher than the reference product, but T _MAX and S _MAX are lower.

Further, in Example 4 where the GMA copolymerization amount is larger than the above, the restoration ratio (1) and the restoration ratio (2) are higher than the reference product, but S _MAX and Sb are lower than Comparative Example 4.

Therefore, depending on the copolymerization amount of GMA,
Although there are some items that are slightly lower than Comparative Example 4, the restoration ratio (1) and the restoration ratio (2) are all excellent, and can be said to be superior to Comparative Example 4 as a whole.

On the other hand, in Comparative Example 3 in which GMA was not copolymerized, not only T _MAX and S _MAX but also the restoration rate (1)
Also, the restoration rate (2) is lower than that of the reference product.

Comparative Example 1 in which the amount of GMA copolymerized was larger.
In Comparative Example 2 and Comparative Example 2, the restoration rate was unmeasurable (insufficient elongation required for the test).

Therefore, by copolymerizing GMA with 0.02 to 0.5% by weight, preferably 0.05 to 0.2% by weight, an acrylic emulsion type having excellent film properties (including the restoration rate) is obtained. It became clear that an elastic sealing material was obtained.

[0058]

The elastic sealing material according to the present invention is excellent in the miscibility with the filler and the elastic restoring property by copolymerizing a small amount of an ethylenically unsaturated polyfunctional crosslinking monomer. It has become.

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 4H017 AA03 AA31 AB01 AB08 AC01 AC04 AC19 AD05 AD06 AE02 AE03 4J100 AB16S AG70S AJ01R AJ02R AJ08R AJ09R AK32R AL03P AL04P AL05P AL10S AL62S AL63S AL75S AM02FA01 DA02 FA01

Claims (5)

[Claims] 1. (a) 84.5 to 98.88% by weight of an acrylate ester having 4 to 12 carbon atoms in an alkyl group;
(B) 1 to 10% by weight of acrylonitrile and / or methacrylonitrile, (c) α, β-unsaturated carboxylic acid 0.1% by weight.
An elastic sealing material comprising a copolymer of 1 to 5% by weight and (d) 0.02 to 0.5% by weight of an ethylenically unsaturated polyfunctional crosslinking monomer. 2. The copolymer has a glass transition temperature of -20.
The elastic sealing material according to claim 1, wherein the temperature is from 0 ° C. to −80 ° C. 3. The weight average molecular weight of the copolymer is 10,000 to 3.
3. The elastic sealing material according to claim 1, wherein the amount is 1,000,000. 4. The elastic sealing material according to claim 1, wherein the amount of the (d) ethylenically unsaturated polyfunctional crosslinking monomer used is 0.05 to 0.2% by weight. 5. The elastic sealing material according to claim 1, wherein the (d) ethylenically unsaturated polyfunctional crosslinking monomer is a glycidyl group-containing monomer.