JPS6255559B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing an adhesive composition for carpet lining which has excellent storage stability and blister resistance. In recent years, there has been a strong trend in carpet lining processing to increase the drying temperature of the dryer in order to increase the drying speed. However, this increase in drying temperature does not improve the drying speed, but on the other hand, it may cause blistering.
bring about an undesirable phenomenon. This phenomenon occurs because a film is formed on the surface of the adhesive layer when it dries, and the film is lifted by the internal water vapor. Recent changes in carpet processing technology have led to the use of polypropylene, which has poor air permeability, as the primary backing material and the use of nylon for the pile, making the blister phenomenon more likely to occur. This phenomenon results in a contradiction in that the drying temperature of the dryer cannot be increased. Therefore, in order to improve productivity by increasing drying temperature, it is essential to develop an adhesive composition with good blister resistance. Conventionally, various techniques have been known to obtain adhesives with good blister resistance, but considering the nature of the blister generation mechanism, a method that utilizes heat-sensitive thickening properties is considered to be the most advantageous (for example, 1977-95749, 1977-126242, 1977-126242, 1972
-139136 etc.). In addition to the above-mentioned patent, the method for heat-sensitive thickening or gelling is disclosed in Japanese Patent Publication No. 45
-26978, Special Publication No. 47-19604, Special Publication No. 40-21427, etc. are already known. However, even with these methods, depending on the conditions of use, the storage stability of the adhesive composition at high temperatures often deteriorates. Particularly when a carpet processor manufactures an adhesive composition using a latex composition that has already been heat-sensitized, in addition to the storage stability of this adhesive composition, the storage stability of the latex composition during storage is also important. required. In this way, it is difficult to satisfy both blister resistance and storage stability, especially storage stability at high temperatures, at the same time, but even products with poor storage stability at high temperatures can be stored below the temperature at which they thicken. Although there are no particular problems, it is desirable to have a material that positively satisfies both blister resistance and storage stability at high temperatures. Therefore, the present inventors conducted extensive studies on various formulations, etc. with the aim of obtaining an adhesive composition with good blister resistance and excellent storage stability at high temperatures. The inventors have surprisingly discovered that when the temperature dependence of the viscosity of the composition satisfies certain conditions, a good adhesive composition can be obtained that simultaneously satisfies blister resistance and storage stability at high temperatures, leading to the present invention. did. That is, the present invention relates to an adhesive composition in which natural rubber or synthetic rubber latex or resin emulsion (hereinafter referred to as latex) contains a filler, a thickener, and a heat-sensitive additive.
The viscosity below is measured with a BM type viscometer at 6 rpm.
Viscosity within 120 seconds at any desired point temperature in the temperature range of 10,000 to 40,000 cps and 60 to 100℃
This is a method for producing an adhesive composition for carpet lining having good storage stability and blister resistance, which is characterized by blending additives so as to increase the viscosity to 100,000 cps or more. The present invention will be explained in detail below. Latexes used in the present invention include natural rubber, synthetic rubber latex such as styrene-butadiene rubber latex, carboxy-modified styrene-butadiene rubber latex, acrylonitrile-butadiene latex, and acrylic emulsion, vinyl chloride emulsion, and ethylene-vinyl acetate. Refers to all latexes commonly used for carpet backing, such as resin emulsions such as emulsions. The fillers and thickeners used in the present invention are used as additives constituting the adhesive composition for carpet backing. Antiaging agents and the like may also be included. Furthermore, the heat-sensitive additives used in the present invention include polyalkylene oxide, polyether polyformal, polyvinyl methyl ether, polyalkylene oxide-modified polysiloxane, etc., which are generally called heat-sensitive gelling agents, as well as water-soluble polyamide and starch. structure at a certain temperature, as seen when adding heat-sensitive thickeners such as methylcellulose, egg protein, polyphosphates, nonionic emulsifiers with cloud points, etc.
It refers to all additives whose function changes and which alter the properties of latexes and latex compositions. In the present invention, heat-sensitive auxiliaries such as ammonia, borates, zinc white, urea, and other polyvalent metal salts, double salts, and complex salts, which change the heat-sensitive temperature and thickening properties when used in combination with the above additives, and nonions Stabilizers such as , anionic emulsifiers are also included among the heat-sensitive additives. The heat-sensitive additive in the present invention is blended so that its viscosity exhibits temperature dependence as shown below. That is, the viscosity of the adhesive composition is 60-100
BM within 120 seconds, preferably within 60 seconds at a certain temperature in the temperature range of ℃, preferably 60-80℃
Blend so that the viscosity increases to 100,000 cps or more when measured with a type viscometer at 6 rpm. The temperature dependence of viscosity varies depending on the type of latex and the type of heat-sensitive additive to be blended, so the amount to be added cannot be determined uniformly. Preferred compounds and amounts added as heat-sensitive additives (parts by weight relative to 100 parts by weight of latex solid content) are polyalkylene oxide 0.5 to 15;
Preferably 1 to 7, polyether polyformal, polyvinyl methyl ether, and polyalkylene oxide modified polysiloxane 0.1 to 10,
Preferably 0.5-5, water-soluble polyamide 0.5-20,
Preferably it is 1-10, starch 1-30, preferably 5-20. Salts, double salts, complex salts, etc. of ammonia, borates, zinc white, urea, and other polyvalent metals used together with additives are
0.05-10, preferably 0.3-5, nonionic and anionic emulsifiers 0.05-5, preferably 0.1-3. If the temperature at which viscosity starts to thicken is less than 60°C, the stability of the composition deteriorates when it is necessary to store it at a relatively high temperature such as in summer, making it impractical. On the other hand, if the thickening start temperature exceeds 100°C, satisfactory blister resistance cannot be obtained. The viscosity when thickened is
Similarly, satisfactory blister resistance cannot be obtained when the amount is less than 100,000 cps. Also, the time required for thickening
If it exceeds 120 seconds, blistering will occur. Therefore, as in the present invention, the viscosity below 60℃ is 10,000~
Adhesive compositions that have a viscosity of 100,000 cps or more within 120 seconds at any desired temperature in the temperature range of 60 to 100°C by blending a heat-sensitive additive with an adhesive composition that has a viscosity of 40,000 cps are considered to have good storage properties. Stability,
Provides blister resistance. Here, the arbitrary target temperature is a temperature at which viscosity is desired to be increased, which is below the temperature at which blistering occurs, and is set according to the drying conditions of the carpet. Next, the present invention will be specifically explained with reference to Examples. The formulation and evaluation method used are shown below. (1) Compound Latex *1 100 parts by weight (solid content) Filler *2 350 parts by weight Thickener *3 Adjust the appropriate amount as follows. Solid content 75% Viscosity 26000 cps (BM type 6 rpm) Various heat-sensitive additives shown in Table 1 are blended into this adhesive composition. *1 Carboxy-modified styrene-butadiene latex manufactured by Nippon Synthetic Rubber Co., Ltd. 0593 *2 Calcium carbonate manufactured by Nitto Funka Co., Ltd. SS30 *3 Sodium polyacrylate manufactured by Toagosei Co., Ltd.
A20P (2) Evaluation method Blister resistance Shubang heater (manufactured by Rinnai) Gas pressure 280mm water column Distance to base fabric 15cm Raw fabric 20m x 15cm Primary base fabric PP pile Nylon Coating amount 1.3Kg/m ² Blister evaluation method The adhesive composition in the above amount is quickly and uniformly spread and applied onto the original fabric using a glass rod, a rubber spatula, or the like. The coated original fabric was placed on a well-ventilated wire gauze, placed under a swiveling heater under the above conditions, and dried for 3 minutes. Count the number of blisters that occur and judge according to the following criteria. Criteria Grade 5 No blisters Grade 4 Total number of blisters 10 or less Grade 3 Total number of blisters 30 or less Grade 2 Total number of blisters 50 or less Grade 1 Full-face blisters Storage stability BM type in a thermostatic chamber Measure with a viscometer at 6 rpm. Criteria ○ 60℃ No change after one week or more △ 60℃ Thickening and gelation after one day × 60℃ Thickening and gelation after one day or less Examples 1 to 3, Comparative Examples 1 to 4 Polyalkylene oxide modification There are three types of polysiloxane: polyalkylene oxide-modified polysiloxane (A) with a cloud point of 35°C, polyalkylene oxide-modified polysiloxane (B) with a cloud point of 75°C, and non-heat-sensitive polyalkylene oxide-modified polysiloxane (C), and others. Using the heat-sensitive additives listed in Table 1, the viscosity at the time of compounding the adhesive composition shown above was 26,000 cps, and the compounding conditions were changed so that the viscosity at each temperature range changed as shown in Table 1. Seven types of adhesive compositions were obtained. Table 1 shows the results of the temperature dependence of viscosity, blister resistance, and storage stability of the obtained composition. From the results in Table 1, the viscosity below 60℃ is
When it exceeds 40,000 cps, the blister resistance may be good, but the storage stability of the composition is poor (Comparative Examples 1 and 2). In addition, in the case of a composition that does not have a rapid viscosity increase in the temperature range of 60 to 100°C (Comparative Example 4) and a composition that rapidly thickens at a temperature exceeding 100°C (Comparative Example 3), It can be seen that the blister properties are not improved at all. Furthermore, when the temperature at which the viscosity rapidly increases is 80°C or higher, the blister resistance is not completely improved (Example 2). Examples 4 and 5 Comparative Examples 5 and 6 Formulation of the adhesive composition shown above using raw potato starch with a gelatinization temperature of 60 to 70°C and raw corn starch and borax with a gelatinization temperature of 80 to 90°C Four types of adhesive compositions were obtained by changing the compounding conditions so that the viscosity at each temperature range varied as shown in Table 2, with the viscosity at 26,000 cps. Table 2 shows the temperature dependence, blister resistance, and storage stability of the obtained composition. Since raw potato starch has a high viscosity when gelatinized, it has good blister resistance and good storage stability (Example 4). In the case of raw corn starch, the gelatinization temperature is high and the viscosity when gelatinized is low, so the storage stability is good, but the blister resistance is poor (Comparative Example 6). Therefore, by adding an additive such as borax that increases the viscosity when gelatinized, a composition with good storage stability and good blister resistance was obtained (Example 5).

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【table】

[Table] Example 6, Comparative Example 7 Compounds were blended and evaluated in the same manner as in Example 1, except that the compound formulation was as shown in Table 3. Comparative example 7 is based on the conventional technology, but the 60 to 100
It did not reach 100,000 cps or more within 120 seconds in the temperature range of °C, and the blister resistance was insufficient.

【table】

【table】

Claims (1)

[Claims] 1 Natural rubber or synthetic rubber latex or resin emulsion (hereinafter abbreviated as latex etc.)
In an adhesive composition containing a filler, a thickener, and a heat-sensitive additive,
Added so that the viscosity at temperatures below ℃ is 10,000 to 40,000 cps as measured with a BM type viscometer at 6 rpm, and the viscosity increases to 100,000 cps or more at any desired temperature in the temperature range of 60 to 100 ℃ within 120 seconds. 1. A method for producing a carpet lining adhesive composition having good storage stability and blister resistance, which comprises blending a carpet lining adhesive composition.