Chloroprene Latex Adhesive

Abstract

To provide a chloroprene latex adhesive that makes it possible to easily remove the matter adhering to a portion other than an adherend face during application work.SOLUTION: A chloroprene latex adhesive contains: a chloroprene latex mixture (a) 100 pts.wt. comprising 60-80 pts.wt. of chloroprene latex (a1) with a toluene dissolution transparency of 4 cm or more and 20-40 pts.wt. of chloroprene latex (a2) with a toluene dissolution transparency of less than 4 cm, the chloroprene latex (a1) and (a2) each having a solid content of 40-60%; a benzoic acid-based plasticizer (b) 20-40 pts.wt.; and a pH modifier 2-10 pts.wt.SELECTED DRAWING: None

Description

[Technical field]

[0001] This invention relates to chloroprene latex adhesives. [Background technology]

[0002] Conventionally, chloroprene latex adhesives have been known which are applied using a spray gun or the like to both or one side of a porous substrate, that is an adherend, and then the coated surfaces are bonded together; specifically, one-component chloroprene latex adhesives are known which are used to bond foam materials used in vehicle interior parts, furniture such as seat chairs and sofas, bedding, pillows, etc., or to bond urethane foams together (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication 2000-219859 [Patent Document 2] Patent Publication No. 2017-222804 DISCLOSURE OF THEINVENTION [Problem to be solved by the invention]

[0004] When applying chloroprene latex adhesive with a spray gun, the adhesive discharged from the spray gun often splashes onto areas other than the surface to be adhered, and ends up on the worker's hands, arms, etc.

[0005] The attached adhesive (hereinafter referred to as the deposit) can be removed relatively easily before it dries, but once it dries it becomes stuck to the attachment surface (so-called "adherent") and in this state it is not easy to remove the deposit.

[0006] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide a chloroprene latex adhesive which makes it possible to easily remove any deposits that have adhered to surfaces other than the surface to be adhered during application or the like. [Means for solving the problem]

[0007] The invention of claim 1 for solving the above problem is as follows: Solids content is 40-60%. 60 to 80 parts by weight of a chloroprene latex (a1) having a toluene-soluble transparency of 4 cm or more as defined below, and 20 to 40 parts by weight of a chloroprene latex (a2) having a toluene solubility transparency of less than 4 cm as defined below, A total of 100 parts by weight of a chloroprene latex mixture (a) obtained by mixing 20 to 40 parts by weight of a benzoic acid-based plasticizer (b); The chloroprene latex adhesive contains 2 to 10 parts by weight of a pH adjuster. Toluene dissolution transparency: Transparency (expressed in cm) measured based on JIS K 0102:2016 for a solution obtained by dissolving 1 part by weight of a resin film obtained by drying chloroprene latex resin at room temperature in 10 parts by weight of toluene.

[0008] In the following, the chloroprene latex (a1) having a toluene-dissolved transparency of 4 cm or more is abbreviated to "high transparency latex (a1)", and the chloroprene latex (a2) having a toluene-dissolved transparency of less than 4 cm is abbreviated to "low transparency latex (a2)".

[0009] The invention of claim 2 is the chloroprene latex adhesive of claim 1, in which the pH adjuster is glycine. Effect of the Invention

[0010] The chloroprene latex adhesive of the present invention contains a chloroprene latex mixture (a) obtained by mixing a high-transparency latex (a1) and a low-transparency latex (a2), and therefore, during application using a spray gun or the like, any material adhering to surfaces other than the adherend can be easily removed, and the adhesive has sufficient adhesive strength on the adherend. [Brief description of the drawings]

[0011] [Figure 1] Front view of the substrate used for adhesiveness evaluation BEST MODE FOR CARRYING OUT THEINVENTION

[0012] The chloroprene latex mixture (a) constituting the chloroprene latex adhesive of the present invention is a chloroprene latex mixture (a) obtained by mixing a high-transparency latex (a1) and a low-transparency latex (a2). The high-transparency latex (a1) and the low-transparency latex (a2) are not particularly limited as long as they are both chloroprene latexes having a solid content of 40 to 60%, and commercially available products can be used.

[0013] Specifically, multiple chloroprene latexes with solid content of 40-60% were prepared and dried to obtain dried products, and then 1 part by weight of each of these dried products was dissolved in 10 parts by weight of toluene (hereinafter, this is referred to as the latex-toluene solution).

[0014] Next, fill a transparency meter specified in JIS K 0102:2016 "Testing Method for Industrial Wastewater" with this latex-toluene solution, look through it from the top to the bottom, and let the solution flow out from the bottom until the double cross on the signboard can be clearly identified for the first time. Read the scale (cm) on the water surface when the double cross on the signboard can be clearly identified for the first time, and this is the toluene transparency of the chloroprene latex.

[0015] Among the chloroprene latexes whose toluene transparency is measured in this way, the one having a toluene transparency of 4 cm or more is called high transparency latex (a1), and the one having a toluene transparency of less than 4 cm is called low transparency latex (a2).

[0016] Next, 60 to 80 parts by weight of the high transparency latex (a1) and 20 to 40 parts by weight of the low transparency latex (a2) are mixed to a total of 100 parts by weight to obtain 100 parts by weight of chloroprene latex mixture (a). Regarding the mixing ratio, for example, when the high transparency latex (a1) is 60 parts by weight, 40 parts by weight of the low transparency latex (a2) is mixed, and when the high transparency latex (a1) is 80 parts by weight, 20 parts by weight of the low transparency latex (a2) is mixed to obtain 100 parts by weight of chloroprene latex mixture (a).

[0017] As the benzoic acid-based plasticizer (b), a commercially available product can be used, for example, Adeka Cizer PN-6122 (trade name) manufactured by ADEKA Corporation.

[0018] In order to increase the initial adhesive strength, the chloroprene latex adhesive of the present invention is preferably blended with a pH adjuster (c) to adjust the pH to the range of 7.0 to 10.0. As the pH adjuster (c), glycine, alanine, phenylalanine, glutamic acid, etc. can be used, and among these, glycine is preferred.

[0019] Then, 100 parts by weight of the chloroprene latex mixture (a) is mixed with 20 to 40 parts by weight of a benzoic acid-based plasticizer (b) and 2 to 10 parts by weight of a pH adjuster (c) to obtain the chloroprene latex adhesive of the present invention. EXAMPLES

[0020] As chloroprene latex, the following products were prepared: Skyprene Latex SL-390 (solid content 50-54%) manufactured by Tosoh Corporation, Denka Chloroprene Latex FB-80 (solid content 54-56%) manufactured by Denka, and DISPERCOLL C84 (solid content 54.5-55.5%) manufactured by Covestro. The toluene dissolution transparency of these products was measured as follows.

[0021] These chloroprene latexes were dried at room temperature to prepare each dried product, which was then dissolved in toluene at a ratio of 10 parts by weight per 1 part by weight of each dried product to obtain each latex-toluene solution.

[0022] Each latex-toluene solution was filled into an AS ONE Corporation transparency meter (product name: ST-30) and the toluene transparency was measured. The results are as follows. SL-390: 4.0cm FB-80: 0.5cm C84: 1.5cm

[0023] From the above measurement results, SL-390 is a high transparency latex (a1), and FB-80 and C84 are low transparency latexes (a2).

[0024] Next, these high transparency latex (a1) and low transparency latex (a2) were mixed in the weight ratios shown in Tables 1 and 2 to prepare 100 parts by weight of each of the chloroprene latex mixtures (a) of Examples 1 to 10 and Comparative Examples 1 to 9.

[0025] Next, benzoic acid plasticizer (b), manufactured by ADEKA Cizer PN-6122 (product name), and glycine as a pH adjuster were prepared and mixed in the weight ratios shown in Tables 1 and 2 to obtain each of the chloroprene latex adhesives (hereinafter simply referred to as adhesives) of the examples and comparative examples.

[0026] The removability and adhesiveness of each of the adhesives in these Examples and Comparative Examples were evaluated as follows.

[0027] <Removability> Each adhesive in the Examples and Comparative Examples was touched with the thumb and index finger, and in this state the thumb and index finger were rubbed together. If the adhesive came together after rubbing and did not remain on the fingers, it was judged as passing (◯); if the adhesive remained on the fingers or became fine granular and did not come together, it was judged as failing (×).

[0028] <Adhesiveness> As a substrate 1 for evaluating the adhesiveness of the adhesive of the present invention, a urethane foam manufactured by Inoac Corporation, product name: Color Foam EMO (8 x 18 x t2.5 cm), is prepared. Figure 1 is a front view of the substrate 1. Next, the substrate 1 is folded at the center in the longitudinal direction, i.e., along folding line 2 shown by the dashed line in Figure 1, and 12 mm masking tape is attached to the top and bottom ends in the folding direction. In an environment of 20°C, each composition of the examples and comparative examples is sprayed onto the substrate at 70 g / m. 2 Apply the foam to the surface and then bend it one minute after application. If the foam pieces stay together, it is considered a pass (○), and if they do not stay together, it is considered a fail (×).

[0029] The evaluation results of each adhesive of the Examples and Comparative Examples are shown in Tables 1 and 2, respectively. [Table 1]

[0030] [Table 2]

[0031] According to the evaluation results shown in Table 1, the removability and adhesion of each of the adhesives in Examples 1 to 10 were all acceptable.

[0032] On the other hand, according to the evaluation results shown in Table 2, at least one of the removability and adhesion of each of the adhesives of Comparative Examples 1 to 9 was unacceptable.

[0033] Specifically, in Comparative Example 1 in which the chloroprene latex mixture (a) consisted only of high transparency latex (a1), the adhesion was unacceptable.

[0034] Comparative Examples 2 and 3 in which the chloroprene latex mixture (a) consisted only of the low-transparency latex (a2) showed unacceptable removability.

[0035] In Comparative Example 4, in which the amount of the high transparency latex (a1) exceeded 80 parts by weight, the adhesion was unacceptable.

[0036] Comparative Example 5, in which the amount of high transparency latex (a1) was less than 60 parts by weight, failed in both removability and adhesion.

[0037] Comparative Example 6, in which the amount of the benzoic acid plasticizer (b) was less than 20 parts by weight, failed in terms of removability, while Comparative Example 7, in which the amount of the benzoic acid plasticizer (b) was more than 40 parts by weight, failed in terms of adhesion.

[0038] Comparative Example 8, in which the amount of pH adjuster (c) was less than 2 parts by weight, showed unsatisfactory adhesiveness. This is presumably because the amount of pH adjuster (c) was too small and sufficient adhesiveness was not achieved.

[0039] Comparative Example 9, in which the blending amount of the pH adjuster (c) exceeded 10 parts by weight, failed in both removability and adhesion.

[0040] That is, the chloroprene latex adhesive of the present invention has a solid content of 40 to 60%, and contains a total of 100 parts by weight of chloroprene latex mixture (a) obtained by mixing 60 to 80 parts by weight of high transparency chloroprene latex (a1) and 20 to 40 parts by weight of low transparency chloroprene latex (a2), 20 to 40 parts by weight of benzoic acid plasticizer (b), and 2 to 10 parts by weight of a pH adjuster, and it has been verified that this chloroprene latex adhesive has the required adhesiveness and can easily remove deposits adhered to surfaces other than the adherend surface during application or the like, which is the problem to be solved by the present invention. [Explanation of symbols]

[0041] 1 Base material 2. Folding lines

Claims

1. Solid content is 40-60%. 60 to 80 parts by weight of a chloroprene latex (a1) having a toluene dissolution transparency of 4 cm or more as defined below, and 20 to 40 parts by weight of a chloroprene latex (a2) having a toluene dissolution transparency of less than 4 cm as defined below; A total of 100 parts by weight of a chloroprene latex mixture (a) obtained by mixing 20 to 40 parts by weight of a benzoic acid-based plasticizer (b); 2 to 10 parts by weight of a pH adjuster, Chloroprene latex adhesive. Toluene dissolution transparency: Transparency (cm) measured according to JIS K 0102:2016 for a solution obtained by dissolving 1 part by weight of a resin film obtained by drying a chloroprene latex resin at room temperature in 10 parts by weight of toluene.

2. 2. The chloroprene latex adhesive of claim 1, wherein the pH adjuster is glycine.

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