JPH0440394B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an adhesive for hard vinyl chloride resin, and more specifically, it can reduce the occurrence of solvent cracks in conventional hard vinyl chloride resin adhesive products, and has good storage stability. This invention relates to adhesives for hard vinyl chloride resins. Hard vinyl chloride resin products using conventional hard vinyl chloride resin adhesives develop cracks called solvent cracking in areas where stress is high over time, which can eventually lead to failure. There were cases. As countermeasures, we will first consider methods such as changing only the solvent that dissolves the vinyl chloride resin in the conventional adhesives mentioned above, or changing the resin to be dissolved, and as a construction method, we will consider methods such as applying hot air treatment for a long time after bonding. is being done. However, at present, all of these conventional countermeasures have the following drawbacks and have not been put to practical use.
In other words, the conventionally proposed methods of changing the solvent have problems with solubility, stability, construction methods, etc.
On the other hand, methods in which resins other than vinyl chloride resins are dissolved have drawbacks such as not only increased costs but also adverse effects on chemical resistance, adhesive strength, etc. In view of the current situation, the present inventor developed a hard vinyl chloride-based resin that has good performance such as adhesive strength, storage stability, and drying speed, is low in cost, and can particularly reduce the occurrence of solvent cracking compared to conventional resins. As a result of intensive study to provide adhesives for
70 parts by weight of cyclohexanone and 3 to 30 parts by weight of acetone phenone; 100 parts by weight of a mixed solvent containing one type of solvent,
An adhesive for a hard vinyl chloride resin, characterized by being made by dissolving a vinyl chloride resin. In the present invention, 100 parts by weight of a mixed solvent having the above composition is essential for use in dissolving vinyl chloride resin, but this is because if cyclohexanone is less than 10 parts by weight, storage stability is poor and drying speed is fast;
If the amount of acetophenone exceeds 3 parts by weight, solvent cracking is likely to occur, and if the amount of acetophenone is less than 3 parts by weight, it is difficult to reduce solvent cracking, and if it exceeds 30 parts by weight, storage stability deteriorates. It's because it's undesirable. In the present invention, more preferably 20 to 50 parts by weight of cyclohexanone and 5 to 50 parts by weight of acetophenone.
20 parts by weight and at least one solvent selected from the group consisting of acetone, tetrahydrofuran, methyl ethyl ketone, toluene, xylene, ethyl acetate, butyl acetate, propyl acetate, and dioxane, particularly preferably acetone and tetrahydrofuran. Mixed solvent 100 containing 40 to 70 parts by weight of at least one solvent selected from the group consisting of hydrofuran, methyl ethyl ketone, toluene, and xylene.
Parts by weight may be suitably used. In the present invention, the vinyl chloride resin to be dissolved in the above mixed solvent is mainly composed of vinyl chloride homopolymers and copolymers of vinyl chloride and other monomers that can be copolymerized with vinyl chloride. It contains a copolymer as a component, and such copolymers include, for example, vinyl chloride-ethylene copolymer, vinyl chloride-ethylene copolymer,
Examples include vinyl acetate copolymers. The amount of these resins dissolved may be selected depending on the viscosity required for the intended adhesive, but is preferably 5 to 50 parts by weight per 100 parts by weight of the mixed solvent. This specification means that if the amount of dissolved resin is less than 5 parts by weight, the solution viscosity is too low and the workability is poor, while if the amount of dissolved resin is more than 50 parts by weight, the solution viscosity is too high and the workability is poor. lower,
Moreover, this is because it takes a great deal of time and effort to dissolve such a large amount of resin. The adhesive of the present invention may contain compounding agents such as fillers, stabilizers, pigments, plasticizers, and rubber components depending on the purpose of use. Also,
The hard vinyl chloride resin products to which the adhesive of the present invention is applied are those manufactured from vinyl chloride resins that do not contain plasticizers or contain only a small amount of plasticizers. Moreover, the above-mentioned vinyl chloride resin refers to not only vinyl chloride homopolymers but also copolymers containing vinyl chloride as a main component among copolymers of vinyl chloride and other monomers that can be copolymerized with vinyl chloride. These copolymers include:
Examples include vinyl chloride-ethylene copolymer resin, vinyl chloride-vinyl acetate copolymer resin, and the like. Furthermore, the adhesive of the present invention is suitably applied to products of resin compositions in which a small amount of other resins such as the above-mentioned vinyl chloride homopolymer and/or the above-mentioned vinyl chloride copolymer resin are mixed. be able to. The shape of the hard vinyl chloride resin product is not particularly limited, and can be applied to any shape such as a pipe, plate, tank, or rod. Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples. In each example, "%" and "parts" mean "% by weight" and "parts by weight" unless otherwise specified. Examples 1 to 6 and Comparative Examples 1 to 5 Vinyl chloride-vinyl acetate copolymer (vinyl acetate
15%) of each of 11 types of mixed solvents having the compositions shown in Examples 1 to 6 and Comparative Examples 1 to 5 in Table 1 below.
Adhesive of the invention 6 dissolved in 100 parts of each
Seeds and five comparative adhesives were obtained. For each adhesive sample of the present invention and for comparison thus obtained, adhesive strength, storage stability, limit open time, and solvent cracking tests were conducted using the following methods, and the results are summarized in Table 2 below. to compare and display. Adhesive strength test: The end of a hard vinyl chloride resin pipe with a diameter of 13 mm is heated in heated glycerin to harden it, and the end of another unsoftened pipe with the same diameter is pushed into the softened end. The end of the softened tube is expanded in diameter to form a female tube. On the other hand, the unsoftened tube used for this insertion was used as a male tube, and after applying each adhesive sample to the outer surface of the male tube and the inner surface of the female tube, the two tubes were immediately joined and heated at a temperature of 20℃. Leave for 15 minutes and 2 hours. Thereafter, this joint tube is tested by applying tension at a tensile rate of 10 mm per minute using a tensile tester at a temperature of 20°C, and the adhesive strength is calculated by dividing the maximum load at this time by the adhesive area. Storage stability test: After placing each adhesive sample in a glass container and sealing it,
Observe the solution state of each sample when it is left in a -20°C freezer for 5 days. Limit open time test: Each adhesive sample was applied to a polyethylene terephthalate film at 20°C using a #24 bar coater, then left in a room at 20°C, and when the coated surfaces were pressed together with a roll, the two layers of adhesive Find the standing time until it becomes easy to peel off at the interface. Solvent cracking test: As shown in Figure 1, the length is 2000mm, the outer diameter is 60mm,
Hard PVC resin pipe 1 with a wall thickness of 4.1 mm and a length of 500 mm
A hard vinyl chloride resin pipe 2, which is otherwise the same as the resin pipe 1, is joined with a hard vinyl chloride resin joint 4 using 5 g of each adhesive sample obtained above, and left at room temperature for 2 hours. After fixing both ends of each joined resin pipe 3 obtained by joining in this way with 5 and 5',
A triangular member 6 with a thickness h (50 mm) is inserted under the center of the joined resin pipe 3, bent to apply stress to the center, both ends are sealed, and left in an atmosphere of -10°C for 10 days. Next, from the upper surface of the center of each bonded resin pipe 3, that is, from the part of maximum tensile stress, a width of 6 mm and a length of 90
A test piece S of mm is taken, and the tensile strength of each test piece S is calculated at 10 mm per minute using a tensile tester at a temperature of 20°C. The tensile strength when the above test was conducted without applying adhesive was 515 Kg/cm ² . Therefore, if the tensile strength in the above-mentioned solvent cracking test conducted by applying an adhesive sample is significantly lower than the tensile strength of 515 kg/cm ² when no adhesive is applied, the applied adhesive will cause the test piece to This means that solvent cracking occurs to a large extent, making it easier to destroy. In other words, as shown in Figure 1, even if the distance is far from the joint location, if the extent of the stress is as shown in Figure 1, as shown in the test results of the comparative example, the point of maximum tensile stress is the conventional adhesive applied to the joint location. The solvent contained in the agent often causes large amounts of solvent cracking, making it easy to break.

【table】

【table】

[Table] As is clear from the results in Table 2, when each of the adhesives of the present invention of Examples 1 to 6 whose compositions are shown in Table 1 was used, the adhesive strength and storage stability were good. The long critical open time allows for good workability during construction, and in addition to this, the tensile strength in the solvent cracking test never decreased to below 515 kg/cm ² when no adhesive was applied. There is no, or even if there is, there is only a slight decline,
Especially excellent. However, when the adhesives of Comparative Examples 1, 3, and 4 were used, the tensile strength in the solvent cracking test was particularly poor in that the decrease to 515 Kg/cm ² or less appeared, and on the other hand, the adhesives of Comparative Examples When adhesives 2 and 5 are used, the tensile strength in the solvent cracking test is good with almost no decrease to below 515 Kg/ ^cm2 , but the storage stability is poor and the adhesive becomes jelly-like. The coating operation becomes difficult and is not preferable.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view showing one embodiment of a solvent cracking test for an adhesive. 1, 2...Hard vinyl chloride resin pipe, 3...1
and 2 joined resin pipe, 4...joint, 6...triangular material,
S...Test piece.

Claims (1)

[Claims] 1 Containing 10 to 70 parts by weight of cyclohexanone and 3 to 30 parts by weight of acetophenone, further selected from the group consisting of acetone, tetrahydrofuran, methyl ethyl ketone, toluene, xylene, ethyl acetate, butyl acetate, propyl acetate, and dioxane. Mixed solvent 100 containing at least one solvent
An adhesive for hard vinyl chloride resin, characterized in that it is made by dissolving vinyl chloride resin in parts by weight.