Adhesive composition for bus panels

Abstract

To provide an adhesive composition for use in bath panels, designed for composite materials (coated steel sheets / gypsum boards), which exhibits superior workability when bonding the composite materials together, and demonstrates superior durability during drying after the bonding process.SOLUTION: An adhesive composition contains an acryl emulsion (A) composed of 10-90 pts.mass of an acryl emulsion (a1) with a solid content of 20-80 mass% and a polymer Tg (glass transition temperature) of 0°C or less and 10-90 pts.mass of an acryl emulsion (a2) with a solid content of 20-80 mass% and a polymer Tg of 20°C or higher. Relative to 100 pts.mass of the acryl emulsion (A), the composition additionally contains: 0.05-20 pts.mass of a modified polyvinyl alcohol (B) containing an acetoacetyl group with a degree of saponification of 95% or more; and 0.05-10 pts.mass (calculated as solid content) of an anionic surfactant (C).SELECTED DRAWING: None

Description

[Technical field]

[0001] This relates to an adhesive composition for composite materials (painted steel sheet / gypsum board) used in bus panels. [Background technology]

[0002] In bathrooms, composite bath panels are sometimes used as a partition between the bathroom and the outside.

[0003] Acrylic emulsion adhesives are often used as adhesives for bonding composite materials.

[0004] When composite materials are bonded together, there is a demand for adhesive compositions that exhibit excellent workability and, after drying following bonding, exhibit excellent durability.

[0005] When bonding composite materials, a coating device such as a roll coater is used, but if the solid content of the emulsion-based adhesive separates from the water, the adhesive thickens and cannot be bonded properly. In addition, after drying after bonding, the materials are exposed to high temperature and high humidity environments, so there is a demand for an adhesive composition that will not peel off even in such environments. Patent Document 1 is a publication relating to a thermal recording adhesive sheet that is excellent in recording sensitivity and recording running property and is suitable for distribution management applications, but there is room for improvement in using this composition as an adhesive composition for composite materials used as bus panels. The use time of an aqueous emulsion-isocyanate-based compound or an isocyanate-based polymer that can be significantly extended The use time of an aqueous emulsion-isocyanate-based compound or an isocyanate-based polymer that can be significantly extended The use time of an aqueous emulsion-isocyanate-based compound or an isocyanate-based polymer that can be significantly extended Patent Document 2 is a publication relating to a two-component application type fast-curing adhesive, and a manufacturing method and bonding method thereof, which are used in the wood processing industry, etc., for doors and panels produced by flash bonding or V-cut bonding of a core material and a surface material, or for laminated lumber produced by bonding multiple laminas. As with Patent Document 1, there was room for improvement in using this composition as an adhesive composition for composite materials used as bath panels. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent Publication No. 10-181200 [Patent Document 2] Patent Publication No. 2002-220575 DISCLOSURE OF THEINVENTION [Problem to be solved by the invention]

[0007] To obtain an adhesive composition for composite materials used for bus panels, which shows excellent workability when bonding composite materials and shows excellent durability after drying after bonding. [Means for solving the problem]

[0008] 10 to 90 parts by mass of an acrylic emulsion (a1) having a solid content of 20 to 80% by mass and a polymer Tg (glass transition temperature) of 0°C or lower; 10 to 90 parts by mass of an acrylic emulsion (a2) having a solid content of 20 to 80% by mass and a polymer Tg of 20° C. or higher; For 100 parts by mass of the acrylic emulsion (A) containing 0.05 to 20 parts by mass of a modified polyvinyl alcohol (B) having an acetoacetyl group and a degree of saponification of 95% or more, The adhesive composition contains an anionic surfactant (C) in an amount of 0.05 to 10 parts by mass in terms of solid content. Effect of the Invention

[0009] This adhesive composition is for composite materials used in bath panels, and shows excellent workability when bonding composite materials together, and shows excellent durability after drying after bonding, thereby providing a comfortable living environment. BEST MODE FOR CARRYING OUT THEINVENTION

[0010] The present invention will be described in detail below.

[0011] The acrylic emulsion (A) contains an acrylic emulsion (a1) having a solid content of 20 to 80% by mass and a polymer Tg of 0°C or lower, and an acrylic emulsion (a2) having a solid content of 20 to 80% by mass and a polymer Tg of 20°C or higher.

[0012] The polymer Tg is a calculated Tg determined by the following Fox formula.

[0013] 1 / (Tg(K))=Σ(Mi / Tgi) (In the formula, Mi represents the mass fraction of monomer i constituting the polymer, and Tgi represents the glass transition temperature (K) of the homopolymer of monomer i.)

[0014] The solid content of the acrylic emulsion (a1) having a polymer Tg of 0° C. or lower is 20 to 80% by mass, more preferably 35 to 65% by mass. The solid content of the acrylic emulsion (a2) having a polymer Tg of 20° C. or higher is also 20 to 80% by mass, more preferably 35 to 65% by mass.

[0015] The amounts of the acrylic emulsion (a1) having a polymer Tg of 0°C or less and the acrylic emulsion (a2) having a polymer Tg of 20°C or more added are 10 to 90 parts by mass of the acrylic emulsion (a1) having a polymer Tg of 0°C or less and 10 to 90 parts by mass of the acrylic emulsion (a2) having a polymer Tg of 20°C or more per 100 parts by mass of the acrylic emulsion (A).

[0016] An example of an acrylic emulsion (a1) having a solid content of 20 to 80% by mass and a polymer Tg of 0° C. or less is commercially available from AICA Kogyo Co., Ltd. under the product name UL-2606 (polymer Tg: -42° C., solid content: 50%), and an example of an acrylic emulsion (a2) having a polymer Tg of 20° C. or more is commercially available from AICA Kogyo Co., Ltd. under the product name A-25K (polymer Tg: 47° C., solid content: 48%).

[0017] The amount of the modified polyvinyl alcohol (B) having an acetoacetyl group and a degree of saponification of 95% or more is preferably 0.05 to 20 parts by mass, and more preferably 0.1 to 15 parts by mass, per 100 parts by mass of the acrylic emulsion (A).

[0018] The modified polyvinyl alcohol (B) having an acetoacetyl group and a degree of saponification of 95% or more is commercially available from Mitsubishi Chemical Corporation under the trade name Gohsenex Z-200 (degree of saponification: 99% or more).

[0019] When adding a modified polyvinyl alcohol (B) having an acetoacetyl group with a degree of saponification of 95% or more, it can be dissolved in water and added. The amount of water is about four times the amount of the modified polyvinyl alcohol (B) having an acetoacetyl group with a degree of saponification of 95% or more.

[0020] The amount of the anionic surfactant (C) added is 0.05 to 10 parts by mass, and more preferably 0.1 to 5 parts by mass, calculated as solid content, per 100 parts by mass of the acrylic emulsion (A).

[0021] The amount of the anionic surfactant (C) added is 0.05 to 10 parts by mass, and more preferably 0.1 to 5 parts by mass, calculated as solid content, per 100 parts by mass of the acrylic emulsion (A). The anionic surfactant (C) is a product of Kao Corporation called Emeral 2F. - 30 (solid content: 30%), Product name: LATEMURU AD-25 (solid content: 24%), Product name: PEREX OT-P (solid content: 70%) and product name: Neopelex G-15 (solid content: 16%) are commercially available.

[0022] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples. Note that all parts are by weight. EXAMPLES

[0023] <Preparation of Adhesive Composition of Example 1> 50 g of UL-2606 (a1) and 50 g of A-25K (a2) were weighed out and mixed until homogenous to obtain acrylic emulsion (A). Separately, 1.25 g of Gohsenex Z-200 was dissolved in 5 g of water. This and Emal 2F - 0.84 g (solid content: 0.25 g) of No. 30 was added to the previously prepared acrylic emulsion (A) and stirred until it became uniform.

[0024] In addition, ULD-1 used in Comparative Examples 1 to 6 is an acrylic emulsion (solid content: 48%) manufactured by AICA Kogyo Co., Ltd., with a polymer Tg of 15°C, Gohsenex Z-320 is a modified polyvinyl alcohol having an acetoacetyl group with a degree of saponification of 92 to 94% manufactured by Mitsubishi Chemical Corporation, and Emulgen 120 and Emulgen 1108 are nonionic surfactants manufactured by Kao Corporation, and the solid content of each is 100%. Although Emulgen 1108 is a liquid product, it is expressed as a solid content for convenience.

[0025] In addition, since the surfactants have different concentrations and the dilution rates are changed to make them easier to add, Tables 1 and 2 show only the solid content. <Roll coater workability> The test was carried out using a two-roll coater, product name: MTH-45 / S, manufactured by Sugii Iron Works Co., Ltd. One roll was made of SUS and had a size of 150φ×450mm, and the other roll was made of EPT rubber and had a size of 233φ×450mm.

[0026] Two rolls were placed in contact with each other, 1.5 kg of the composition was placed on them, and the two rolls were rotated from top to bottom at the contact portion of the rolls at a rotation speed of 30 m / min.

[0027] After one hour of operation, if the viscosity was less than three times the initial viscosity, it was marked as "good", while if the viscosity was three times or more, it was marked as "bad".

[0028] The viscosity was measured using a BH type viscometer manufactured by Toki Sangyo Co., Ltd., a No. 3 rotor, at 10 rpm, and 1 minute (measurement temperature: 20±2° C.). <High temperature and humidity creep properties> A gypsum board measuring 45 mm x 85 mm x 9 mm thick and a painted steel plate measuring 25 mm x 100 mm x 0.5 mm thick were prepared. The end of a 12 mm wide masking tape was attached 50 mm from the end of the painted steel plate. This was to prevent the composition that had penetrated into the gypsum board from affecting the creep test to be performed later.

[0029] At 5℃, 60g / m2 applied to plaster board 2 The composition was applied with a bar coater so that the adhesive was applied to the short side of the gypsum board. After leaving it to stand for 30 seconds, the coated steel plate was placed on the end of the masking tape (the side opposite to the 50 mm position) and the short side of the gypsum board, and the plate was pressed down at 6.5 kPa for 10 seconds and left to stand for 24 hours. The adhesive area was 25 mm x 50 mm.

[0030] A 200g weight is hung from the end of the coated steel plate of this test piece, and the unbonded part of the gypsum board is fixed horizontally. This test piece is placed in a 60℃ / 95%RH environment.

[0031] The evaluation criteria were as follows: if the sample could be held for 60 minutes, it was considered a pass (○), and if the sample could not be held for 60 minutes, it was considered a fail (×). The results are shown in Tables 3 and 4.

[0032] Examples 1 to 10 are adhesive compositions containing 100 parts by mass of acrylic emulsion (A) including 10 to 90 parts by mass of acrylic emulsion (a1) having a solid content of 20 to 80% by mass and a polymer Tg (glass transition temperature) of 0°C or less, and 10 to 90 parts by mass of acrylic emulsion (a2) having a solid content of 20 to 80% by mass and a polymer Tg of 20°C or more, 0.05 to 20 parts by mass of modified polyvinyl alcohol (B) having an acetoacetyl group and a saponification degree of 95% or more, and 0.05 to 10 parts by mass of an anionic surfactant (C) converted into solid content, and passed both the roll coater workability and the high temperature and high humidity creep properties.

[0033] Comparative Example 1, which used UL-2606 with a polymer Tg of -42°C and ULD-1 with a polymer Tg of 15°C, and Comparative Example 2, which used A-25K with a polymer Tg of 20°C or higher and ULD-1 with a polymer Tg of 15°C, passed the roll coater workability test but failed the high temperature and high humidity creep test.

[0034] In Comparative Example 3, which used Gohsenex Z-320, a modified polyvinyl alcohol having an acetoacetyl group with a degree of saponification of 92 to 94%, the roll coater workability was acceptable, but the high temperature and high humidity creep property was unacceptable. - In Comparative Example 4, in which No. 30 was not added, the roll coater workability was unacceptable, but the high-temperature and high-humidity creep property was acceptable.

[0035] In Comparative Examples 5 and 6, which used the nonionic surfactants Emulgen 120 and Emulgen 1108, the roll coater workability was unsatisfactory, and high-temperature, high-humidity creep properties were not confirmed.

[0036] [Table 1]

[0037] [Table 2]

[0038]

Table 3

[0039]

Table 4

Claims

1. 10 to 90 parts by mass of an acrylic emulsion (a1) having a solid content of 20 to 80% by mass and a polymer Tg (glass transition temperature) of 0° C. or lower; 10 to 90 parts by mass of an acrylic emulsion (a2) having a solid content of 20 to 80% by mass and a polymer Tg of 20° C. or higher; For 100 parts by mass of the acrylic emulsion (A) containing 0.05 to 20 parts by mass of a modified polyvinyl alcohol (B) having an acetoacetyl group and a degree of saponification of 95% or more, An adhesive composition comprising an anionic surfactant (C) in an amount of 0.05 to 10 parts by mass, calculated as solid content.

2. 10. The composition of claim 1 which is a composite adhesive composition for use in bus panels.

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