JPH0323671B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to carpet backing adhesive compositions with improved blister resistance, viscosity stability over time, and adhesive strength. Currently, when lining tufted carpets, knitted carpets, foot carpets, etc.
As an adhesive, an aqueous dispersion in which a filler, a dispersant, a stabilizer, a thickener, etc. are added to a polymer dispersion as necessary is used. This adhesive is often left unused for long periods of time and exposed to high temperatures of nearly 40 degrees Celsius in the summer. However, if the viscosity stability of the adhesive is poor, when used for carpet lining, the amount of adhesive applied may be uneven, or
In addition, it has a subtle effect on the penetration of the adhesive into the carpet pile (tuft), resulting in phenomena such as a lack of a desirable texture, a decrease in the adhesive strength of the backing fabric, and the pile falling out, which significantly reduces the product value. This will result in a lower level of performance. Therefore, it is very important to stabilize the viscosity of the adhesive over time. On the other hand, during the carpet drying process, when the moisture in the adhesive applied to the carpet evaporates, a portion of the adhesive is lifted, causing a bulge (blister) on the back side of the carpet. The so-called blister phenomenon is often observed, which seriously impairs the appearance of the carpet, and great efforts are expended in removing the blisters.
However, in recent years, in order to increase productivity in carpet manufacturing, drying at high temperatures and high wind speeds has become common.Also, due to the shortage of juute fabrics, polypropylene products whose primary base fabric is low in air permeability and water absorption are being used. is transitioning to. As a result, the blister phenomenon has become more likely to occur, and this has become a very serious hindrance in the carpet manufacturing process. As an adhesive composition for carpet lining with excellent blister resistance and viscosity stability over time,
56-44191 contains a combination of Orukatu polysiloxane compound and nonionic surfactant,
139136 shows a formulation of polyalkylene oxide compounds. However, for these compositions, when the blister resistance is improved by these methods, the adhesion strength is usually lower than when this treatment is not adopted, and the demand for improved adhesion is not met. However, it has been difficult to satisfy the requirements of blister resistance and stability of viscosity over time. Therefore, the inventor of the present invention has conducted extensive research in order to develop an adhesive composition for carpet lining that has excellent blister resistance, viscosity stability over time, and strong adhesive strength. Surprisingly, contrary to the conventional tendency, blister resistance and durability are improved by the combination of a conjugated diene copolymer latex containing merging units and an amino acid compound. The present inventors have discovered that it is possible to obtain an excellent composition that has good day stability and does not exhibit a decrease in adhesive strength, and has completed the present invention. It is an object of the present invention to provide an adhesive composition for carpet backing having improved blister resistance, viscosity stability over time, and adhesive strength.

A carpet lining adhesive comprising a filler and a conjugated diene copolymer latex containing a monomer unit represented by the formula: (wherein R ₁ and R ₂ are hydrogen and C _{1 to 8} alkyl) This is achieved by using an adhesive composition containing 0.05 to 5 parts by weight of an amino acid compound per 100 parts by weight of the solid content of the copolymer latex. The conjugated diene polymer latex used in the present invention has the general formula

[Formula] (In the formula, R ₁ and R ₂ represent hydrogen and a C _1-8 alkyl group)
It is a latex obtained by copolymerizing a monomer represented by the above formula, a diene monomer, and, if necessary, a vinyl monomer copolymerizable with these monomers. general formula

Monomers represented by the formula (in which R ₁ and R ₂ are the same as above) include N-methylol acrylamide, N-methylol methacrylamide, N-n-butoxymethyl acrylamide, and N-n-butoxymethyl methacrylamide. Amides and the like can be mentioned. The copolymer content of this component is 0.1 to 10% by weight, preferably 0.5 to 5% by weight.
Weight%. If it is less than 0.1% by weight, the adhesive strength will not be improved, and if it exceeds 10% by weight, the viscosity stability over time will decrease. Examples of the conjugated diene monomer include butadiene, isoprene, 1.3-bentadiene, etc., and the content in the copolymer is 10 to 99.9% by weight. Vinyl monomers that can be copolymerized with the above two types of monomers include aromatic vinyl monomers such as styrene and α-methylstyrene, unsaturated nitrile monomers such as acrylonitrile and methacrylonitrile, and methyl (meta)
Esters of acrylic acid and methacrylic acid such as acrylate, ethyl (meth)acrylate, and butyl acrylate, unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, and maleic acid, and hydroxyl groups, amic acids, glycidyl groups, and sulfonic groups, etc. Examples include monomers having a functional group. The content in the copolymer is 0 to 89.9% by weight. An example of the copolymer latex used in the present invention is butadiene-styrene (meth)acrylic acid-
N-methylol(meth)acrylamide copolymer, butadiene-styrene-N-methylol(meth)acrylamide copolymer, butadiene-styrene-methylmethacrylate-N-methylol(meth)acrylamide copolymer, butadiene-
Styrene-(meth)acrylic acid-N-n-butoxymethylacrylamide copolymer, butadiene-
Styrene-itaconate-N-methylol (meth)
Examples include latexes of acrylamide copolymers. The amino acid compound used in the present invention is not particularly limited as long as it has a carboxyl group and an amino group in the molecule, such as glycine, alanine,
α-amino acids such as valine, leucine, isoleucine, phenylalane, and proline; oxyamino acids such as serine, threonine, tyrosine, and oxybroline; sulfur-containing amino acids such as cysteine, cystine, and methionine; acidic amino acids such as aspartic acid and glutamic acid; lysine; Examples include basic amino acids such as arginine, β-alanine, γ-aminobutyric acid, anthranilic acid, and p-aminobenzoic acid. These amino acid compounds can be used as they are or as salts such as alkali salts. The amount used is preferably in the range of 0.05 to 5 parts by weight per 100 parts by weight of solid content of the conjugated diene copolymer latex. If it is less than 0.05 parts by weight, a sufficient effect in preventing blistering will not be obtained, and a sufficient effect will not be obtained in suppressing the odor of the latex composition during and after drying, which is one of the features of the present invention. . If it exceeds 5 parts by weight, the viscosity stability of the adhesive composition over time becomes poor and is not practical. More preferably 0.1~
It is 3 parts by weight. In the present invention, an organopolysiloxane heat-sensitizing agent can be used if necessary. Organopolysiloxane heat-sensitive agent is a compound used as a heat-sensitive coagulant, for example,
This is a compound described in No. 44191, etc. Particularly preferred compounds are alkylene oxide modified organopolysiloxanes. The amount used is usually 3 parts or less, preferably 0.005 to 1.5 parts by weight, per 100 parts by weight of solid content of the copolymer latex. If it exceeds 3 parts by weight, the adhesive composition will have poor viscosity stability over time, making it difficult to obtain a practical composition. The amount of amino acid to be used may be within the above-mentioned range, and an optimum amount may be used depending on the content of the functional monomer in the copolymer latex. Fillers used in the present invention include ground calcium carbonate, aluminum hydroxide, clay, talc, and light calcium carbonate. Among these, heavy calcium carbonate or aluminum hydroxide, which are commonly used for carpet treatment, are preferred. The amount used is usually 50 to 600 parts by weight per 100 parts by weight of the solid content of the copolymer latex. If it is less than 50 parts by weight, the blister resistance will not be sufficient, and if it exceeds 600 parts by weight, it will be difficult to obtain satisfactory adhesive strength. Preferably it is 150 to 500 parts by weight. In the composition of the present invention, it is not necessary to add a nonionic surfactant in order to improve the viscosity stability over time, but the addition is not limited to this. However, the addition of a large amount of surfactant inevitably leads to a decrease in adhesive strength, thereby causing the characteristic of the present invention to be lost. The adhesive composition of the present invention may further contain conventional compounding agents such as dispersants, stabilizers, anti-aging agents, vulcanizing agents, vulcanization accelerators, antifoaming agents, thickeners and pigments, if necessary. can be included. The adhesive composition of the present invention can be applied to all fabrics or fabrics in which a polymer dispersion is applied to the back side of tufted carpets, knitted carpets, foot carpets, etc. to bond carpet piles or bond secondary base fabrics to carpets. It can be applied to carpets made of nonwoven fabric. This composition can be applied to the carpet by white backing, mesh pasting, jute pasting, and pasting of a secondary backing material made of a synthetic material such as polypropylene. It can also be used for the above purposes in a foamed state, such as floss bagging. Next, the present invention will be specifically explained with reference to Examples.
All parts of ingredients in each example are based on solids weight. EXAMPLE The monomer mixtures listed in Table 1 were polymerized at 50° C. to a reaction rate of about 95% by a conventional emulsion polymerization method to obtain eight types of copolymer latexes.

[Table] An adhesive composition for carpet lining was prepared by mixing 100 parts by weight of these copolymer latexes with water and the formulation shown in Table 2. The viscosity of these adhesive compositions over time was measured using a B-type viscometer. On the other hand, the obtained composition was prepared using polypropylene as the base fabric and nylon as the pile (filament loop pile, 1/2
1.5Kg on 8 inch gauge tufted carpet
(WET)/ ^m2 , then backing with 9 oz.
After drying for 10 minutes in a dryer at 160° C. and a hot air speed of 8 m/sec, the state of blistering of the adhesive was observed with the naked eye. Adhesive strength of each composition to the above carpet is 1.4
Kg (WET)/m ² , coated with juute, rolled and crimped at a temperature of 130°C and a hot air speed of 2.
After drying for 15 minutes in a dryer at m/s, 20℃, humidity 60%
JISL using carpet left for 24 hours under
-1021, the peel strength of juute was measured. The above results are shown in Table 2.

【table】

[Table] From the results in Table 2, the latex containing N-methylolacrylamide as a copolymer component alone has extremely poor blister resistance (Experiment No. 1), but adding an amino acid compound improves the blister resistance. It can be seen that both the adhesive strength is improved (Experiment Nos. 7 to 9). Further, even if a copolymer latex outside the scope of the present invention is used in combination with an amino acid, a carpet backing adhesive with improved blister resistance and adhesive strength cannot be obtained.

Claims (1)

[Scope of Claims] 1. A conjugated diene containing a monomer unit represented by the general formula [Formula] (wherein R ₁ and R ₂ represent hydrogen and a C _1-8 alkyl group) in a copolymer. In a carpet lining adhesive composition comprising a copolymer latex and a filler, 0.05 to 5 parts by weight of an amino acid compound is blended into the adhesive composition per 100 parts by weight of the copolymer latex solid content. An adhesive composition for carpet lining, characterized in that: