JPH024714B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention uses polyoxyethylene alkyl phenol ether sulfate or polyoxyethylene alkyl ether sulfate as an emulsifier for polymerization, and aliphatic conjugated diene monomers, ethylenically unsaturated carboxylic acids, and monomers copolymerizable with these. The present invention relates to an improved carpet backing agent containing a copolymer latex as a main component. The copolymer latex used in carpet backing agents provides the backing agent with mechanical and chemical stability and pigment dispersion stability, and provides adhesive strength, appropriate texture, and dimensional stability to the backed workpiece. Give gender etc. In recent years, backing agents for carpets have been increasing the proportion of fillers in order to reduce costs. Therefore, the adhesive strength of the backing agent decreases, resulting in a hard texture. Conventional copolymer latexes used in these backing agents include butadiene/
Examples include styrene/ethylenically unsaturated carboxylic acid copolymer. Backing agents using these latexes cannot satisfy both properties of soft texture and high adhesive strength when formulated with a large amount of filler. This has been a problem in carpet processed products. In order to solve this problem, we conducted various studies on the production method of copolymer latex for use in carpet backing agent formulations, and found that polyoxyethylene alkyl phenol ether sulfate and/or A backing agent using a copolymer latex with a particle size of 1000 to 2500 Å obtained by using polyoxyethylene alkyl ether sulfate has excellent performance with a good balance between soft texture and high adhesive strength. I discovered that. The present invention uses a monomer mixture consisting of 40 to 60% by weight of an aliphatic conjugated diene, 0.5 to 8% by weight of an ethylenically unsaturated carboxylic acid, and 32 to 59.5% by weight of a compound copolymerizable with these.

[Formula] (R is an alkyl group having 6 to 14 carbon atoms, n is an integer of 2 to 75, and X is Na, K or _NH4 ) and/or polyoxyethylene alkyl phenol ether sulfate and/or with the general formula R '-O(CH ₂ CH ₂ O) _o -SO ₃ X (R' is an alkyl group having 6 to 14 carbon atoms, n is 2 to 75
, X is Na, K or NH ₄
The present invention provides a carpet backing agent containing an aliphatic conjugated diene copolymer latex having a diameter of 2,500 Å and a toluene-insoluble content of the copolymer of 60 to 90% by weight, and an inorganic filler. The present invention will be explained in detail below. Emulsifier for polymerization The present invention uses the general formula

[Formula] (R is an alkyl group having 6 to 14 carbon atoms, preferably 8 to 12 carbon atoms, n is an integer of 2 to 75, and X is Na, K, NH ₄ ) Polyoxyethylene alkyl phenol ether sulfate and general formula R'-O
( _CH2CH2O ) _{o -SO3X} (R' is an alkyl group having 6 to ₁₄ carbon atoms, preferably 8 to 12 carbon atoms, n is an integer of 2 to 75
Polyoxyethylene alkyl ether sulfates (X is Na, K, _NH4 ) are used as emulsifiers in emulsion polymerization. These emulsifiers may be used alone or in combination of two or more. The average particle size necessary for producing a copolymerized latex with a soft texture and high adhesive strength, which is the object of the present invention, is influenced by the amount of emulsifier and the method of use. Emulsifiers other than those mentioned above may be used in small amounts in combination without adversely affecting the objectives and effects of the present invention. The usage ratio of this emulsifier is 0.05 to 6 relative to the total monomers.
It is preferable to use it within the range of 0.05% by weight, and if it is less than 0.05% by weight, the polymerization stability will be poor, and in the case of carpet backing agents with a high filler content, high adhesive strength can be obtained with soft texture. I don't like it. On the other hand, if it exceeds 6% by weight, the adhesive strength of the carpet backing agent decreases, which is not preferable. The average particle diameter of the copolymer latex is preferably 1000 to 2500 Å, even more preferably 1500 to 2500 Å. If it is less than 1000 Å, the stability of the backing agent in highly filled formulations will be poor, and if it exceeds 2500 Å, the adhesive strength will decrease. Although the method of using the emulsifier during polymerization is not particularly limited, examples of preferred methods of using the emulsifier are shown below. An emulsifier within the above range is used from the beginning of polymerization (batch polymerization). In accordance with the method in which a portion of all monomers is first polymerized and the remaining monomers are continuously added and polymerized, a portion of the emulsifier is similarly added to the initial polymerization system and the remaining portion is added during the polymerization. At this time, the emulsifier may be added separately from the monomer, or the monomer may be emulsified with the emulsifier and then added. Some emulsifiers are added after polymerization to stabilize the latex. At this time, the final emulsifier concentration in the latex is within the scope of the present invention. There are other methods. The characteristics of the copolymer latex obtained using this emulsifier are the same as those using conventionally used sodium dodecylbenzene sulfonate, sodium lauryl sulfate, and sodium alkyl diphenyl ether sulfonate. It has the characteristics that a soft latex can be obtained even with a monomer composition, and that the particle size can be easily controlled. Furthermore, the toluene-insoluble part of the copolymer latex of the present invention (the latex was dried on a plate to form a film, 0.3 g of it was added to 100 ml of toluene, left at room temperature for 48 hours, and filtered through a 120-mesh wire mesh). (determined by drying and weighing what remains on the wire mesh) is 60 to 90% by weight. If it is less than 60% by weight, it will be difficult to obtain adhesive strength, and if it exceeds 90% by weight, the texture will be hard. A carpet backing agent using this latex has excellent filler filling properties, and the carpet processed product thereof exhibits soft blowing properties with little temperature dependence and also has excellent adhesive strength. Polymerization Monomer The aliphatic conjugated diene is used in a range of 40 to 60% by weight to provide the copolymer latex with appropriate flexibility and adhesive strength. Butadiene is preferred as the aliphatic conjugated diene. Examples of ethylenically unsaturated carboxylic acids include itaconic acid, acrylic acid, and methacrylic acid. These are used in an amount of 0.5 to 8% by weight of the total monomers. It is preferably used in a range of 2 to 6% by weight. If the amount is less than 0.5% by weight, coagulation is likely to occur during polymerization, and the mechanical stability of the resulting latex is poor. If more than 8% by weight is used, the latex will become thickened with alkali and will be impractical. These ethylenically unsaturated carboxylic acids may be used alone or in combination of two or more. Particularly preferred is itaconic acid methacrylic acid or a combination of itaconic acid and acrylic acid. By copolymerizing an ethylenically unsaturated carboxylic acid within the above range, the mechanical and chemical stability of the resulting copolymerized latex is improved. Note that the use of a dicarboxylic acid monomer has an effect on polymerization stability, and its combined use with a monocarboxylic acid is preferable. The carpet backing agent of the present invention using this latex has excellent water retention, coating suitability, and storage stability. Furthermore, the film strength of the backing agent itself is increased, and the adhesive strength of the carpet (strength for adhesively fixing carpet fibers) is improved. These properties are further improved when a high filler content is used. Other compounds that can be copolymerized with aliphatic conjugated dienes and ethylenically unsaturated carboxylic acids include aromatic vinyl compounds, alkyl (meth)acrylates,
Examples include vinyl cyanide compounds. Examples of the aromatic compound include styrene, α-methylstyrene, p-methylstyrene, vinyltoluene, and chlorostyrene, among which styrene is preferred. Examples of the alkyl (meth)acrylate include methyl acrylate, ethylene acrylate, butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, and 2-ethylhexyl methacrylate, among which methyl methacrylate is preferred. Examples of vinyl cyanide compounds include acrylonitrile and methacrylonitrile, with acrylonitrile being preferred. These copolymerizable compounds can be used alone or in combination of two or more. In particular, copolymerization of methyl methacrylate improves stability during polymerization. These compounds are used in a range of 32-59.5% by weight. The copolymer latex according to the present invention uses polyoxyethylene alkyl phenol ether sulfate or polyoxyethylene alkyl ether sulfate as an emulsifier, and its particle size is 1000-2500 Å.
belongs to. When the particle size of the latex is less than 1000 Å or more than 2500 Å, the adhesive force of the carpet backing agent is low. Moreover, if it exceeds 2500 Å, stability during polymerization is poor and coagulation is likely to occur. The production of the copolymer latex used in the present invention is carried out in the same manner as the production of ordinary carboxy-modified conjugated diene copolymer latex, except that a specific emulsifier is used and a relatively large amount of ethylenically unsaturated carboxylic acid is used. be exposed. Polymerization is usually carried out by redox-based polymerization initiation using a combination of 100 to 300 parts of water per 100 parts of monomer, 0.5 to 3 parts of potassium persulfate as a polymerization initiator, and 0.05 to 2 parts of sodium bisulfite as a reducing agent. agent is used. As the molecular weight modifier, for example, 0.1 to 6 parts of carbon tetrachloride and tertiary decyl mercaptan can be used. Other electrolyte chelating agents, buffering agents, dispersing agents, PH adjusting agents, etc. can be added as necessary. All of these polymerization initiators, molecular weight regulators, and other auxiliary agents may be charged into the reactor before the start of polymerization, or some of them may be charged before the start of polymerization, and the rest may be added during polymerization. Polymerization temperature is 40-80℃, preferably 50-70℃
℃ is good. Polymerization time is 15-40hrs, preferably 20hrs
~30hrs. The method for preparing monomers is as follows:
There is a method in which a portion of all monomers is first polymerized and then the remaining monomers are added continuously, and a method in which all monomers are charged at once from the beginning. The former polymerization method allows easy control of particle size and is suitable for producing the copolymer latex of the present invention. The polymerization conversion rate is usually 97% or more, preferably 99% or more. Carpet backing agents are mainly composed of copolymerized latex and inorganic fillers such as calcium carbonate and aluminum hydroxide, and further include dispersants, viscosity stabilizers, crosslinking agents, preservatives, thickeners, etc. depending on the purpose. is used. The backing agent using the copolymer latex according to the present invention contains 400 to 400 parts by weight of the inorganic filler per 100 parts by weight of the latex (as solid matter).
800 parts by weight is possible, and it shows better performance at high filling than conventional ones, and is also economically superior. Next, in order to clarify the present invention, examples and comparative examples will be given and explained. The polymerization method of the copolymer latex used in Examples and Comparative Examples is shown below. In the following, parts and % represent parts by weight and % by weight, respectively. Method for producing copolymer latexes (1) to (11), (14) of Examples and copolymer latexes (A) to (N) of Comparative Examples Table 1 (Example) and Table 2 (Comparative Example) monomer shown
100 parts and emulsifier, plus 4 parts of carbon tetrachloride, 1.5 parts of potassium persulfate, 0.1 part of sodium bisulfite, and water.
150 parts were charged into a stainless steel reactor with an internal volume of 100 L, and copolymer latexes (1) to (11), (14) and (a) to (h) were obtained while stirring at 60°C for 24 hours. In addition, the method of preparing the monomer is to first polymerize 20% of the monomer,
The remaining monomer was then added continuously for 15 hours. The polymerization conversion rate of the obtained latex was 99% or more. The polymerization stability was very good except for (g) and (h), and there was almost no coagulum. Method for producing copolymer latexes (12) and (13) of Examples Monomers and emulsifiers shown in Table 1, further 0.3 part of t-dodecylmercaptan, 0.8 part of potassium persulfate,
0.3 parts of potassium pyrophosphate, 0.05 parts of ethylenediaminetetraacetic acid sodium salt, and 150 parts of water were charged into a 100 L stainless steel reactor, and a copolymer latex was obtained while stirring at 50°C for 24 hours. All monomers were charged from the beginning of polymerization. The polymerization conversion rate of the obtained latex was 99% or more. Polymerization stability is good;
There was almost no coagulum. Evaluation of carpet backing agent Formula of carpet backing agent Copolymer latex (solid content) 100 parts by weight Sodium tripolyphosphate 0.5 Anti-aging agent 1.0 Silicone antifoaming agent 0.05 Heavy calcium carbonate 450 Sodium polyacrylate 1.0 Solid content: 80%, viscosity: 30,000 cp (BM No. 4, 6 rpm) Note: The carpet backing agent is made by adding a dispersant, etc. to the latex, and then adding a filler and dispersing it well.Then, the solid content is 80% and the viscosity is 30,000 cp. Adjust with thickener and water. Test method (1) Adhesive strength JIS L-1021 Backing agent 1300 g/m 2 (wet) or 1500 g/m 2 (wet) or 1500 g/m ² (wet) is applied to a tufted carpet fabric in which the primary base fabric is made of polypropylene and the fiber bundle is made of nylon.
g/m ² (wet), and the peel strength between the primary base fabric and the secondary base fabric after bonding and bonding the secondary base fabric with 8 oz. Measure 20 cm). (Coating amount 1300
The adhesive strength of g/ ^m2 is the adhesive strength of a coating amount of 1500g/ ^m2 . The values are when the temperature is 20°C and the angle is 30°. The larger this value is, the harder the texture is. (3) Film tensile strength The film is made by applying a carpet backing agent onto a polyester sheet to a film thickness of 0.5 mm.
Stack them so that
Heat treat for 20 minutes. This film is cut into dumbbell shapes and pulled at a speed of 100 mm/min using an autograph, and the breaking strength is expressed as the strength at that time.
Note that film strength has a strong correlation with adhesive strength, and those with strong film strength have strong adhesive strength. (4) Water retention Water retention is measured by the paper (No. 51A) absorbency of water in the carpet backing agent. Carpet backing agents with good absorbency have poor water retention. Water retention is a measure of suitability for applying a carpet backing agent, and if it is poor, it may cause uneven coating when applying the carpet backing agent, which is undesirable. Evaluation of water retention is indicated by ◎, 〇, △, and ×. ◎
indicates very good water retention, 〇 indicates good, and × indicates poor water retention.
Note that water retention has a large correlation with adhesive strength, and those with good water retention have strong adhesive strength. Examples and Comparative Examples The copolymer latex obtained above was evaluated as a carpet backing agent, and the results are shown in Tables 1 and 2. Example (1) Examples 1, 2, and 3 are experimental examples using a copolymer latex in which the average particle diameter of the copolymer latex was changed within the scope of the present invention by varying the amount of emulsifier. . (2) Examples 4, 5, and 6 are experimental examples using copolymer latexes in which the number of moles of ethylene oxide added to the emulsifier polyoxyethylene nonylphenol ether sodium sulfate was varied within the scope of the present invention. (3) In Example 7, K salt (No.
This is an experimental example using a copolymer latex obtained using 7) as an emulsifier. (4) Examples 8 and 9 are experimental examples using copolymer latexes in which sodium polyoxyethylene lauryl ether sulfate was used as an emulsifier and the number of moles of ethylene oxide added was varied within the scope of the present invention. (5) Examples 10 and 11 are experimental examples using copolymer latexes in which the monomer components of the copolymer latexes were changed within the scope of the present invention. (6) For the copolymer latexes (Nos. 1 to 11 and 14), a part of the monomer was first polymerized, and the rest was added continuously. In Examples 12 and 13, all monomers were added from the beginning of the polymerization. (7) Example 14 is an experimental example in which sodium polyoxyethylene nonyl phenol ether sulfate and sodium polyoxyethylene lauryl ether sulfate were used in combination as emulsifiers. Comparative Example (1) Comparative Examples 1 and 2 are experimental examples using a copolymer latex obtained with an emulsifier of a type outside the scope of the present invention. (2) Comparative Examples 3 and 4 are experimental examples using copolymer latexes in which butadiene was obtained outside the range of the present invention. (3) Comparative Examples 5 and 6 are experimental examples using copolymer latexes whose particle diameters are outside the range of the present invention. (4) Comparative Examples 7 and 8 are experimental examples using copolymer latexes obtained with an amount of ethylenically unsaturated carboxylic acid outside the range of the present invention. (5) Comparative Examples 9 and 10 are experimental examples using a copolymer latex whose toluene-insoluble content was outside the range of the present invention. Results of Examples 1 to 12 Examples 1 to 14, which were changed within the scope of the present invention, yielded the desired carpet backing agent with a soft texture, strong adhesive strength, strong film strength, and good water retention. . Results of Comparative Examples 1 to 10 Comparative Examples 1 and 2, in which the emulsifier was different from that of the present invention, had weak adhesive strength. In particular, Comparative Example 2 has a significantly hardened texture. In Comparative Examples 3 and 4, the amount of butadiene was varied, and Comparative Example 3, in which the amount was less than the range of the present invention, had strong strength, but the texture was very hard and unbalanced. On the contrary, Comparative Example 4 contains more butadiene than the range of the present invention, so the texture is too soft and the adhesive strength is weak. Comparative example 5,
In No. 6, a copolymer latex whose particle size was outside the range of the present invention was used. Comparative Example 5 had extremely poor water retention and weak adhesive strength due to its small particle size. Comparative Example 6 has a large particle size and therefore has low adhesive strength. Comparative Examples 7 and 8 are backing agents using copolymer latexes with an amount of ethylenically unsaturated carboxylic acid outside the range of the present invention, but the viscosity of the backing agents did not change so drastically over time that it could be evaluated. Comparative Examples 9 and 10 are backing agents using copolymer latexes whose gel contents are outside the range of the present invention. Comparative Example 9, which has a low gel content, has weak adhesive strength. Comparative Example 10, which had a high gel content, had a hard texture and weak adhesive strength.

【table】

[Table] Example 15, Comparative Example 11 Using copolymer latex No. (2) used in Example 2 and copolymer latex (B) used in Comparative Example 2, these copolymer latexes and filling Table 3
A carpet backing agent was prepared and evaluated.

[Table] As a result, the copolymer latex of the present invention (Example 15) has a high filler content of 40 to 800 parts, has a soft texture,
In contrast, conventional latex Comparative Example 10 maintains high adhesive strength at 300 parts of filler, but the adhesive strength decreases significantly and the texture hardens at 400 parts or more. .

Claims (1)

[Scope of Claims] 1 A monomer mixture consisting of 40 to 60% by weight of an aliphatic conjugated diene, 0.5 to 8% by weight of an ethylenically unsaturated carboxylic acid, and 32 to 59.5% by weight of a compound copolymerizable with these, expressed by the general formula [Formula] (R is an alkyl group having 6 to 14 carbon atoms, n is an integer of 2 to 75, and X is Na, K or _NH4 ) and/or polyoxyethylene alkyl phenol ether sulfate and/or with the general formula R '-O(CH ₂ CH ₂ O) _o -SO ₃ X (R' is an alkyl group having 6 to 14 carbon atoms, n is 2 to 75
, X is Na, K or NH ₄
A carpet backing agent containing an aliphatic conjugated diene copolymer latex having a diameter of 2500 Å and a toluene insoluble content of the copolymer of 60 to 90% by weight, and an inorganic filler.