JPH0667993B2 - Method for producing polymer aqueous dispersion - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is a novel resin which exhibits excellent mechanically stable filler dispersibility and particularly excellent adhesion to hydrophobic fibers such as polypropylene, nylon and polyester. To a method for producing an aqueous dispersion of a polymer.

[Prior art]

Conventionally, tufted carpets, upholstery cloth, automobile seats, pile fabrics such as artificial lawns, pile fixation to the fabric, lamination of secondary base fabric, generally for the purpose of imparting dimensional stability and elasticity, A composition in which a high molecular weight aqueous dispersion of SBR latex, natural rubber latex, synthetic resin emulsion or the like is blended with various additives such as an inorganic filler such as calcium carbonate or aluminum hydroxide and a thickener is packed as necessary. ing.

Recently, polypropylene split yarn woven fabrics have been widely used for tufted carpets as primary base fabrics (base fabrics into which piles are inserted) for artificial lawns. However, since this polypropylene fabric is non-polar and has almost no water absorption, the secondary base fabric (backing) peeling strength is not sufficient when backing with a composition containing a conventional polymer aqueous dispersion as a component. Moreover, the pile pull-out strength tends to be insufficient. On the other hand, in the manufacture of carpets and the like, there is a strong tendency to mix a large amount of inexpensive inorganic fillers as a component of the composition in order to reduce the production cost, and therefore the fillers have excellent dispersion and stability, and a large amount of fillers. There is a demand for a low-viscosity polymer aqueous dispersion that does not reduce the adhesive strength when blended with.

[Problems to be solved by the invention]

The present invention is intended to solve the following problems associated with conventional techniques.

(1) The polymer aqueous dispersion produced by the conventional production method does not have sufficient adhesion to the polypropylene base cloth, and as a result, the pile adhesion strength (pulling strength) of the secondary cloth such as carpet is poor. .

(2) The polymer aqueous dispersion produced by the conventional production method lacks the ability to stably mix and disperse a large amount of inorganic filler, and the adhesive strength is remarkably lowered by compounding the filler.

(3) The polymer aqueous dispersion obtained by the conventional production method lacks mechanical stability.

[Means for solving problems]

The present inventors have conducted extensive studies to develop a polymer aqueous dispersion having excellent dispersibility of filler, mechanical stability, and compounding stability, and exhibiting excellent adhesive force to polypropylene fabric. A highly satisfactory aqueous polymer dispersion for the above purpose can be obtained by adding a naphthalene sulfonate formalin condensate using an emulsifier that always contains polyoxyethylene alkylphenyl ether sulfate represented by the structural formula. The present invention has been completed and the present invention has been completed.

That is, the present invention is a compound of the following structural formula [I] and a naphthalenesulfonate formalin condensation as an essential emulsifier when emulsion-polymerizing butadiene, an ethylenically unsaturated carboxylic acid and other ethylenically unsaturated monomers. Used with
The resulting polymer aqueous dispersion was produced by a Marlon type stability tester (rotation speed 1000 rpm), and the formed solid matter was
A method for producing an aqueous polymer dispersion, which comprises 0.02% by weight or less.

Structural formula [I] (Structure) The butadiene used in the present invention is preferably 10 to 90% by weight in order to internally plasticize the dry film of the polymer water dispersion and give elasticity to give a preferable feeling to the carpet after backing. However, if the proportion is 10 parts by weight or less, the elasticity of the film is insufficient and the texture of the carpet after backing becomes rigid, making it unusable for practical use. On the other hand, when it is 90 parts by weight or more, the strength of the film decreases, and as a result, the peeling strength of the secondary base cloth of the carpet and the like decreases.

The ethylenically unsaturated carboxylic acid of the present invention is preferably contained in an amount of 0.5 to 10 parts by weight based on all monomers, and one or more kinds may be used. Examples of the ethylenically unsaturated carboxylic acid include acrylic acid, methacrylic acid, itaconic acid, fumaric acid, maleic anhydride, and the like, and these ethylenically unsaturated carboxylic acids are mechanically stable polymer aqueous dispersions. Is a component necessary for improving the stability, freeze stability, dispersibility of the filler, and the adhesion of the film to the substrate.
If the content in 100 parts by weight is 0.5 parts by weight or less, no effect is obtained, and if it is used in excess of 10 parts by weight, the water resistance of the film is lowered, which is not preferable.

Other ethylenically unsaturated monomers used in the present invention include, for example, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, butyl acrylate, butyl methacrylate. Alkyl acrylates such as pentyl acrylate, pentyl methacrylate, hexyl acrylate, hexyl acrylate, heptyl acrylate, heptyl methacrylate, octyl acrylate, octyl methacrylate, octadecyl acrylate, octadecyl methacrylate and the like. Methacrylic acid alkyl ester; ethylenically unsaturated aromatic monomers such as styrene, α-methylstyrene vinyltoluene, chlorostyrene, 2-4-dibromostyrene; acrylonitrile, Unsaturated nitriles such as acrylonitrile; vinyl esters such as vinyl acetate and vinyl propionate; vinylidene halides such as vinylidene chloride and vinylidene bromide; ethylene such as 2-hydroxypropyl acrylate and 2-hydroxyethyl methacrylate. Hydroxyalkyl esters of unsaturated carboxylic acids; glycidyl esters of ethylenically unsaturated carboxylic acids such as glycidyl acrylate, glycidyl methacrylate; and acrylamide, methacrylamide, N-methylolacrylamide, N-methylolmethacrylamide, N-
Examples thereof include butoxymethyl acrylamide and diacetone acrylamide.

These monomers are used to form a polymer main chain with butadiene or as a functional group component, for example, to form intermolecular crosslinks, and to characterize carpet texture, water resistance, etc. , One or more of these monomers is preferably 0 to 89.5 per 100 parts by weight of the total monomers.
Used in parts by weight.

The emulsifier represented by the following structural formula [I] of the present invention is polyoxyethylene alkylphenyl ether sulfate,
n is 2 to 20 An integer, preferably 2 to 5, M is Na, K, NH ₄ and R represents an alkyl group having 1 to 12 carbon atoms. A specific example is Emar NC (Kao Soap Co., Ltd. product). This emulsifier is preferably 0.5 per 100 parts by weight of the total monomer.
~ 5.0 parts by weight may be added. Further, this emulsifier can be used alone or in combination with other emulsifiers such as alkylbenzene sulfonate (Na, K) and sodium lauryl sulfate. If the emulsifier is less than 0.5 parts by weight, the compounding stability at the time of high filling is poor, and there is no effect of preventing the foaming phenomenon at the time of addition, so that it is not preferable. It becomes high and it is difficult to mix a large amount of filler.

The naphthalenesulfonate formalin condensate of the present invention is a compound represented by the following structural formula [II], and preferably n = 1. For example, Disrol SH (product of Nippon Emulsifier Co., Ltd.) can be used.

This naphthalene sulfonate formalin condensate is preferably added halfway when the polymerization rate is 5 to 30%. By doing so, it is possible to obtain an aqueous dispersion of a polymer for backing, which has a low viscosity, a small decrease in strength even when a large amount of a filler is added, and an excellent dispersibility. If a dispersant other than the naphthalene sulfonic acid formalin condensate is used, it is not possible to obtain a backing polymer aqueous dispersion in which a large amount of filler can be blended.

If the naphthalene sulfonate formalin condensate is added at a polymerization rate of less than 5%, a large amount of coagulated product is generated in the dispersion after polymerization, and the polymerization rate is not practical.
If it exceeds 0.5%, the viscosity of the system becomes high and it becomes difficult to stably mix a large amount of the filler, which is not preferable.

The naphthalene sulfonate formalin condensate is used in an amount of 0.5 to 5.0 parts by weight, preferably 0.5 to 1.0 parts by weight, based on 100 parts by weight of all monomers. 0.5
If it is less than part by weight, the viscosity of the system becomes high and a large amount of filler cannot be blended, and if it exceeds 5.0 parts by weight, a large amount of coagulate is generated in the dispersion after polymerization, which is not practical. .

The polymer aqueous dispersion according to the present invention is produced by a batch charging emulsion polymerization method under reaction conditions of a reaction temperature of 0 to 100 ° C. and a reaction time of 5 to 15 hours. For example, a free radical generating catalyst such as KSP obtained by emulsifying and dispersing the above monomer mixture in water.
_{(K 2 S 2 0 8)} , APS ((NH 4) 2 S 2 O 8), aqueous catalyst such as hydrogen peroxide solution, t- butyl hydroperoxide, preferably the oil-based catalyst such as cumene hydroperoxide 50 The emulsion polymerization reaction may be carried out at ~ 70 ° C.
At this time, it is considered that these monomers are solubilized in the micelles of the emulsifier, and the free radicals of the catalyst enter the micelles to start emulsion polymerization.

Further, in the production of a polymer aqueous dispersion, a commonly used additive such as a chain transfer agent (tertiary decyl mercaptan), an antioxidant (hindered phenol), an ultraviolet absorber (benzophenone compound) ethylenediaminetetraacetic acid, etc. It can be used at all. The obtained polymer aqueous dispersion has a pH of 3 to 6 and a viscosity of 50 to 300 cps, but more preferably it is adjusted to pH 8 to 9 with an alkaline substance (sodium hydroxide, potassium hydroxide, etc.).

The polymer aqueous dispersion after the emulsion polymerization reaction is preferably adjusted to a solid content of 50 to 60% by a method such as stripping.

The polymer aqueous dispersion of the present invention is a Marlon type mechanical stability tester (a product of Shinsei Sangyo Co., Ltd.) specified in JIS K-6392-46, and a rotating disk with a rotation speed of 1000 ± 20 rpm is fixed in a test container. The coagulated content in the latex produced when the pressure is applied for 10 minutes is measured. The produced solidified product at this time is 0.02% by weight or less based on the weight of the solid content.

That is, solidification content generation rate (%): C _H , solidification content mass (g): W
d, the sample mass (g): W _I, total solids (%) of the samples: When Ta belongs to.

If the solidification content generation rate is more than 0.02% by weight, the compounding stability becomes unsatisfactory, for example, gelation occurs due to the filler when used for carpet backing, which is not preferable.

〔effect〕

The polymer aqueous dispersion of the present invention thus obtained has excellent dispersibility when a large amount of filler is compounded, and also has excellent mechanical stability and excellent adhesion to hydrophobic fibers such as polypropylene. Not only is it suitable as a resin, but it can also be used as a coating agent for adhesives, paper, fibers, plastics and the like. Further, the production method of the present invention is particularly effective in improving the mechanical stability of a polymer aqueous dispersion having a butadiene content of 60% by weight or more.

Further, the polymer aqueous dispersion of the present invention has less skin surface phenomenon due to drying during storage, and what is surprising is that a carpet is prepared using a backing composition containing the polymer aqueous dispersion of the present invention. When manufactured, it is possible to prevent the occurrence of blisters (boiling inside the adhesive when the adhesive is dried and the adhesive partially blows out to the back surface of the carpet to significantly impair the appearance (phenomenon)). That is an excellent thing.

〔Example〕

Next, the present invention will be described more specifically by way of examples. In addition, "part" and "%" in each example shall be based on weight.

Example 1 120 parts of ion-exchanged water in a nitrogen-substituted autoclave,
Butadiene 60 parts, Styrene 35 parts, Acrylic acid 5 parts, Alkylbenzene sulfonic acid sodium (Neopelex F-25
Kao Soap Co., Ltd. 1.0 part, polyoxyethylene alkylphenyl ether sodium sulfate (Enur NC, Kao Soap Co., Ltd.) 1.0 part, ethylenediaminetetraacetic acid 0.1 part
And 0.5 parts of tertiary dodecyl mercaptan were charged, and 0.5 part of ammonium persulfate was added at a polymerization temperature of 60 ° C. to initiate polymerization. After about 3 hours from the start of polymerization, a naphthalenesulfonic acid formalin condensate (Disrol S
H, 0.5 part of Nippon Emulsifier Co., Ltd. was added to the reaction vessel and reacted until the polymerization rate reached 98% or more. Then with potassium hydroxide
Adjusted the pH to 8.7 and removed and concentrated unreacted monomer by stripping, solid content 50.3%, PH8.5, viscosity 150cp
A polymer aqueous dispersion (A) was obtained. This dispersion (A)
As a result of conducting the stability test of No. 1, it was found that the aggregate was 0 and it was very excellent in stability.

Next, using the above water dispersion (A), the composition shown in Table 1 was prepared to adjust the adhesive compound for carpet backing, and 1400 g (wet) per 1 m ² was applied to a carpet composed of acrylic loop pile and polypropylene primary base cloth. And apply jute as a secondary base cloth
A carpet was prepared by drying in a hot air dryer at ℃ for 10 minutes. Next, this carpet was cut into a width of 5 cm and subjected to a peeling test of a secondary base cloth and a yarn pull-out test of an acrylic loop pile. Moreover, the back surface of the carpet was observed and the blister was judged. The test results are shown in Table 2. From Table 2, the polymer aqueous dispersions of the examples of the present invention show good results.

Example 2 Solid content 50.0% pH 8.3 Viscosity 110 cps in the same manner as in Example 1 except that the emulsifier polyoxyethylene alkylphenyl ether sodium sulfate used in Example 1 was changed to 2.0 parts.
A polymer aqueous dispersion (B) was obtained. The formalin condensate of naphthalene sulfonate (Disroll SH, manufactured by Nippon Emulsifier Co., Ltd.) was added at a polymerization rate of 20.3%.

Thereafter, a stability test was conducted in the same manner as in Example 1 except that the polymer aqueous dispersion (B) thus obtained was replaced with the polymer aqueous dispersion (A) to prepare a carpet, and the peel strength and the peel strength were similarly determined. The yarn removal strength was measured. The test results are shown in Table 2. From Table 2, it was confirmed that the polymer aqueous dispersion of the present invention showed good results.

Comparative Examples 1,2 Naphthalenesulfonic acid formalin condensate (Destrol S
A polymer aqueous dispersion was obtained in the same manner as in Examples 1 and 2 except that H, a product of Nippon Emulsifier Co., Ltd. was not used.

As a result of performing mechanical stability test of these aqueous dispersions,
The solidification rate was 0.1% and 0.3%, respectively. Further, using these aqueous dispersions, a carpet was prepared by carrying out a carpet backing in the same manner as in Example 1 and the results of various performance tests are also shown in Table 2.

Comparative Example 3 Emulsion polymerization was carried out in the same manner as in Example 1 except that polyoxyethylene alkylphenyl ether lactate was not used, and a polymer aqueous dispersion having a solid content of 50.0%, pH 8.7 and a viscosity of 200 cps (E ) Got.

A carpet was prepared in the same manner as in Example 1 except that the polymer aqueous dispersion (E) thus obtained was used, and the peel strength and the yarn removal strength were measured in the same manner. Second result
Shown in the table. It can be seen from Table 2 that in Comparative Example 3, the peeling strength of the secondary base cloth and the yarn removing strength of the pile are both poor, the compounding stability is poor, and the blister phenomenon is also observed. It was confirmed that even if compounded, it has compounding stability and high adhesive strength and is useful as an excellent polymer aqueous dispersion base resin for backing.

Dispersibility: Aqueous polymer dispersion / Heavy calcium carbonate = 100/5
00 was blended and the stirring state when stirring for 10 minutes was observed.

Mixing stability: The adhesive compound composition based on Table 1 was left in a dryer at 50 ° C. for 2 weeks, and the change in viscosity with time was observed. (Difference of ± 5000 cps is bad) Polymerization rate measurement: Nonvolatile matter was measured from the weight measurement result after drying at 110 ° C for 1 hour, which was sampled every hour during the polymerization, and calculated by the following formula.

Blister judgment: The number of adhesive blown out per 10 cm ^{2 of the} back surface of the carpet is shown.

Claims (1)

[Claims] 1. A compound of the following structural formula [I] and a naphthalenesulfonate formalin condensate as an essential emulsifier when emulsion-polymerizing butadiene, an ethylenically unsaturated carboxylic acid and other ethylenically unsaturated monomers. And use
The obtained polymer aqueous dispersion is characterized by having a solidification product content of 0.02% by weight or less based on the weight of the solid content in a Marlon type stability tester (rotation speed 1000 ± 20 rpm). A method for producing an aqueous dispersion. Structural formula [I]