JP6386367B2 - Solvent adhesive - Google Patents

Description

  The present invention relates to a solvent-based adhesive suitable as an adhesive for rigid polyvinyl chloride pipes.

  Conventionally, a solvent-based adhesive containing a resin and an organic solvent has been used as an adhesive for rigid polyvinyl chloride pipes.

  About the adhesive for hard polyvinyl chloride pipes for waterworks, the Japan Water Works Association Standard JWWA S101 has specified the manufacturing method, material specification and quality standard values of adhesive strength, loss on drying, viscosity, and leachability (see Table 1). .

  Conventional hard polyvinyl chloride pipe adhesives have characteristics (including workability) that can be used for nominal diameters of 13A (13mm) to 300A (300mm) in a wide temperature range from winter (low temperature) to summer (high temperature). Therefore, a plurality of organic solvents having different drying speeds are blended and designed, and a relatively large amount (for 100 parts by weight of resin) with respect to a fast-drying low-boiling organic solvent (for example, tetrahydrofuran or methyl ethyl ketone). About 75 parts by weight or more) of slow-drying high-boiling organic solvent (cyclohexanone having a boiling point of 156 ° C.).

  For example, Example 1 of Patent Document 1 includes 200 parts by weight of vinyl chloride-vinyl acetate copolymer resin, 200 parts by weight of tetrahydrofuran, 450 parts by weight of methyl ethyl ketone, and 150 parts by weight of cyclohexanone (vinyl chloride-vinyl acetate copolymer resin 100). Solvent used for joining hard polyvinyl chloride pipes and joints obtained by dissolving in a mixed solvent in which three types of solvents consisting of 75 parts by weight are mixed and adding fine particulate titanium oxide. A mold adhesive composition is described. In Example 5 of Patent Document 1, 150 parts by weight of chlorinated vinyl chloride resin, 350 parts by weight of tetrahydrofuran, 100 parts by weight of methyl ethyl ketone, and 400 parts by weight of cyclohexanone (267 parts by weight with respect to 100 parts by weight of chlorinated vinyl chloride resin) The solvent-type adhesive composition used for joining a rigid polyvinyl chloride pipe and a joint obtained by dissolving in a mixed solvent in which three types of solvents are mixed and adding fine particulate titanium oxide is described. ing.

  As described above, since the conventional hard polyvinyl chloride pipe adhesive uses a relatively large amount of a high boiling point organic solvent, the organic solvent is used in order to ensure sufficient adhesive strength and hygiene. As time for drying, the drying curing for 24 hours after construction is needed. For this reason, the conventional hard polyvinyl chloride pipe adhesive has restrictions on its use, especially for renovations in residences where there are residents, renovations in case of water leakage, etc. is there.

  On the other hand, as an adhesive for rigid polyvinyl chloride pipes containing a resin and an organic solvent, a relatively small amount (75 weights per 100 parts by weight of the resin) with respect to a fast-drying low-boiling organic solvent (for example, tetrahydrofuran or methyl ethyl ketone). The addition of a slow-drying, high-boiling organic solvent (cyclohexanone having a boiling point of 156 ° C.) of about 10 parts by weight is also known.

  For example, in Example 1 of Patent Document 2 and Example 1 of Patent Document 3, 20 wt.% Of chlorinated vinyl chloride resin is used as an adhesive used to connect a vinyl chloride resin pipe and a vinyl chloride resin pipe joint. Parts, 3 parts by weight of Aerosil (thickening agent), 70 parts by weight of tetrahydrofuran, 18 parts by weight of methyl ethyl ketone, and 12 parts by weight of cyclohexanone (60 parts by weight with respect to 100 parts by weight of chlorinated vinyl chloride resin) were blended. An adhesive is described. In Example 5 of Patent Document 3, 25 parts by weight of chlorinated vinyl chloride resin and Aerosil (thickening agent) 7 are used as an adhesive used to connect a vinyl chloride resin pipe and a vinyl chloride resin pipe joint. There is described an adhesive containing 85 parts by weight of tetrahydrofuran, 85 parts by weight of tetrahydrofuran, 10 parts by weight of methyl ethyl ketone, and 5 parts by weight of cyclohexanone (20 parts by weight with respect to 100 parts by weight of chlorinated vinyl chloride resin).

Japanese Patent Laid-Open No. 10-298519 JP 2000-18471 A JP-A-11-335646

  However, according to the study of the present inventor, the addition amount of a slow-drying high boiling organic solvent (cyclohexanone having a boiling point of 156 ° C.) in conventional hard polyvinyl chloride pipe adhesives such as Patent Document 2 and Patent Document 3 is reduced. When the amount is relatively small (less than 75 parts by weight with respect to 100 parts by weight of the resin), the organic solvent component can be dried quickly, resulting in a decrease in the swelling layer at the adhesive interface and a decrease in adhesive strength. It turned out to be.

  The present invention has been made in view of the above-described conventional problems, and an object thereof is to provide a solvent-based adhesive having good workability and exhibiting sufficient adhesive strength and hygiene in a short time after bonding. It is an object.

  The present inventor changed a resin and an organic solvent from conventional solvent-based adhesives in a solvent-based adhesive containing 100 parts by weight of a resin and 400 to 650 parts by weight of an organic solvent, and added an acrylic resin in the resin. Workability is good by containing 10% by weight or more and reducing the content of the organic solvent having a boiling point of 100 ° C. or more in the organic solvent to 100 parts by weight or less with respect to 100 parts by weight of the resin. In addition, the present inventors have found that a solvent-based adhesive exhibiting sufficient adhesive strength and hygiene can be provided in a short time after bonding, and the present invention has been completed.

  The solvent-based adhesive of the present invention is a solvent-based adhesive containing a resin and an organic solvent, and the amount of the organic solvent is in the range of 400 to 650 parts by weight with respect to 100 parts by weight of the resin, The resin contains 10% by weight or more of an acrylic resin, and the content of the organic solvent having a boiling point of 100 ° C. or higher in the organic solvent is in the range of 0 to 100 parts by weight.

  According to the configuration of the present invention, the content of the organic solvent having a boiling point of 100 ° C. or higher in the organic solvent is set to 100 parts by weight or less with respect to 100 parts by weight of the resin, so that a short time after bonding (for example, 2 hours) ), Sufficient adhesive strength is obtained, and the amount of organic matter leached into water and the like when water is passed is sufficiently reduced, thereby providing sufficient hygiene.

  On the other hand, when the organic solvent having a boiling point of 100 ° C. or higher in the conventional solvent-based adhesive is reduced to 100 parts by weight or less, the organic solvent component is quickly dried, resulting in a decrease in the swelling layer at the bonding interface, and the adhesive strength is increased. Although it may fall, according to the structure of this invention, the fall of adhesive strength is suppressed by making the content rate of the acrylic resin in the said resin into 10 weight% or more.

  This is because the acrylic resin is different from the vinyl chloride resin used in conventional solvent-based adhesives and the vinyl chloride-vinyl acetate copolymer resin, which is one of them, with a difference in solubility (solubility parameter ( This is considered to be due to differences in SP value) and mechanical strength properties (tensile strength) (see Table 2).

  Moreover, according to the structure of this invention, since the quantity of the said organic solvent exists in the range of 400-650 weight part with respect to 100 weight part of resin, it has the viscosity suitable for application | coating and is good enforcement Showing gender.

  As described above, according to the present invention, it is possible to provide a solvent-based adhesive having good workability and exhibiting sufficient adhesive strength and hygiene in a short time (for example, 2 hours) after bonding. Therefore, for example, when a water-based hard polyvinyl chloride pipe is bonded using a solvent-based adhesive, the water-based hard polyvinyl chloride pipe bonded in a short time (for example, 2 hours) is used as a water pipe. You can start.

  INDUSTRIAL APPLICABILITY The present invention has an effect that it is possible to provide a solvent-based adhesive having good workability and exhibiting sufficient adhesive strength and hygiene in a short time (for example, 2 hours) after bonding.

It is explanatory drawing for demonstrating the evaluation method of the adhesive strength by the hydraulic fracture test of the solvent-type adhesive agent which concerns on an Example , a reference example, and a comparative example. It is explanatory drawing for demonstrating the measuring method (JISK6850 test method) of the adhesive strength by the tensile shear test of the solvent-type adhesive agent which concerns on an Example , a reference example, and a comparative example. It is a schematic diagram which shows the evaluation kit used for sanitary evaluation of the solvent-type adhesive agent which concerns on an Example , a reference example, and a comparative example. It is a graph which shows the rise (it raises as curing time becomes long) of the tensile shear strength (adhesion strength by a tensile shear test) of the solvent-type adhesive agent which concerns on an Example , a reference example, and a comparative example. It is a graph which shows the comparison of the total organic carbon (henceforth "TOC") amount measured by the sanitary evaluation method of the solvent-type adhesive agent which concerns on an Example , a reference example, and a comparative example.

  Hereinafter, the present invention will be described in detail.

  The solvent-based adhesive of the present invention is a solvent-based adhesive containing a resin and an organic solvent, and the amount of the organic solvent is in the range of 400 to 650 parts by weight with respect to 100 parts by weight of the resin, The resin contains 10% by weight or more of an acrylic resin, and the content of the organic solvent having a boiling point of 100 ° C. or higher in the organic solvent is in the range of 0 to 100 parts by weight.

  When the solvent-based adhesive of the present invention is cured for 2 hours after bonding a hard polyvinyl chloride pipe and a hard polyvinyl chloride pipe joint using the solvent-based adhesive, the strength of the bonded portion is hard polyvinyl chloride. It is preferable that the strength is higher than the strength of the tube and the rigid polyvinyl chloride tube. Thereby, a solvent-based adhesive having higher adhesive strength can be realized. Here, when the hard polyvinyl chloride pipe and the hard polyvinyl chloride pipe joint were bonded using the solvent-based adhesive and then cured for 2 hours, the strength of the bonded portion was determined to be a hard polyvinyl chloride pipe and a hard polyvinyl chloride. Whether the strength is higher than the strength of the pipe can be determined by whether the evaluation result according to the “method for evaluating the adhesive strength of the solvent-based adhesive by the hydraulic fracture test” in the examples described later is “original pipe fracture”.

  When the solvent-based adhesive of the present invention contains tap water for 24 hours inside an evaluation kit prepared by bonding a rigid polyvinyl chloride pipe and a rigid polyvinyl chloride pipe joint using the solvent-based adhesive. Furthermore, it is preferable that the TOC amount of water in the evaluation kit is 200 mg / L or less. Thereby, a solvent-based adhesive with higher hygiene can be realized. Here, when the tap water was sealed for 24 hours inside the evaluation kit prepared by adhering a rigid polyvinyl chloride pipe and a rigid polyvinyl chloride pipe joint using the solvent-based adhesive, Whether the TOC amount of water is 200 mg / L or less is determined by whether the TOC amount measured by the “method for evaluating hygiene of a solvent-based adhesive” in Examples described later is 200 mg / L or less. Can do.

  The resin contains 10% by weight or more, preferably 15% by weight or more of an acrylic resin. By setting the ratio of the acrylic resin in the resin to 15% by weight or more, it is possible to suppress a decrease in adhesive strength due to the organic solvent having a boiling point of 100 ° C. or more being 100 parts by weight or less. More preferably, the resin contains more than 15% by weight of acrylic resin relative to the entire solvent-based adhesive.

  The acrylic resin is a homopolymer or copolymer of (meth) acrylic acid ester. The acrylic resin is preferably a homopolymer of (meth) acrylic acid alkyl ester or a copolymer of (meth) acrylic acid alkyl ester.

  Examples of the alkyl (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, (meth) acrylate-2-ethylhexyl, lauryl (meth) acrylate, and the like. Can be mentioned. These may be used alone or in combination of two or more. Here, “(meth) acryl” means acrylic or methacrylic.

  As the (meth) acrylic acid alkyl ester, methacrylic acid alkyl ester is preferable from the viewpoint of the adhesive strength of the solvent-based adhesive. Moreover, it is preferable that the carbon number of the alkyl group of the said (meth) acrylic-acid alkylester is the range of 1-20, It is more preferable that it is the range of 1-10, It is the range of 1-4. Further preferred.

  The copolymer of (meth) acrylic acid alkyl ester contains a hydrophilic group (hydroxy group, carboxyl group, amino group, amide group, sulfo group) as another monomer to be copolymerized with (meth) acrylic acid alkyl ester. Hydrophobic monomers that are not used may be used, and hydrophilic monomers containing hydrophilic groups may be used.

  Examples of the hydrophobic monomer include nitriles such as (meth) acrylonitrile; olefins such as ethylene, propylene, isobutylene, 1-butene, styrene, and methylstyrene; vinyl formate, vinyl acetate, vinyl propionate, vinyl pivalate, And vinyl esters such as vinyl versatate; and vinyl halide compounds such as vinyl chloride and vinylidene chloride. These may be used alone or in combination of two or more. Here, “(meth) acrylonitrile” means acrylonitrile or methacrylonitrile.

  Examples of the hydrophilic monomer include carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, itaconic acid, fumaric acid, and crotonic acid; hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, and (meth) acrylic. Hydroxyalkyl esters of (meth) acrylic acid such as hydroxybutyl acid; amides such as (meth) acrylamide, N-methylolacrylamide, N, N-dimethylacrylamide, and N-isopropylacrylamide. These may be used alone or in combination of two or more.

  In the acrylic resin, the content of the structural unit derived from the hydrophilic monomer is preferably 50% or less, more preferably 30% or less, and further preferably 10% or less. When the content of the structural unit derived from the hydrophilic monomer is large, the adhesive strength of the solvent-based adhesive may be lowered. In addition, the content of the structural unit derived from the (meth) acrylic acid ester in the acrylic resin is preferably 50% or more, more preferably 70% or more, and further preferably 90% or more. . Thereby, the adhesive strength of the solvent-based adhesive can be improved.

  The weight average molecular weight of the acrylic resin is preferably in the range of 250,000 to 1,000,000, and more preferably in the range of 250,000 to 400,000. If the acrylic resin has a weight average molecular weight of less than 250,000, high adhesive strength may not be obtained. Conversely, when the weight average molecular weight of the acrylic resin exceeds 1,000,000, volume shrinkage due to drying of the organic solvent increases, and stress is applied to the adhesive coating film when the organic solvent is dried after coating, resulting in a decrease in adhesive strength. There is a tendency. On the other hand, when the weight average molecular weight of the acrylic resin exceeds 400,000, the stringiness of the solvent-based adhesive may be deteriorated and the workability may be deteriorated.

  The solvent-based adhesive of the present invention may contain a resin other than an acrylic resin. As the resin other than the acrylic resin, a vinyl resin that is a polymer of an ethylene vinyl monomer is preferable. Specific examples of such vinyl resins include vinyl chloride resins and vinyl acetate resins. As the resin other than the acrylic resin, a vinyl chloride resin is preferable in order to satisfy Japan Water Works Association Standard JWWA S101. These may be used alone or in combination of two or more.

  Examples of the vinyl chloride resin include a vinyl chloride homopolymer, a copolymer of a vinyl chloride monomer and a polymerizable monomer having an unsaturated bond copolymerizable with the vinyl chloride monomer, and a vinyl chloride monomer in the polymer. And a graft copolymer obtained by graft copolymerizing, and a chlorinated vinyl chloride resin obtained by post-chlorinating a vinyl chloride resin. These may be used alone or in combination of two or more.

  The polymerizable monomer having an unsaturated bond is not particularly limited as long as it is a monomer having a radical reactive double bond and copolymerizable with a vinyl chloride monomer by a radical polymerization initiator. Α-olefins such as ethylene, propylene and butylene; vinyl esters such as vinyl acetate and vinyl propionate; vinyl ethers such as butyl vinyl ether and cetyl vinyl ether; methyl (meth) acrylate, ethyl (meth) acrylate, butyl acrylate, (Meth) acrylic acid esters such as phenyl methacrylate; aromatic vinyls such as styrene and α-methylstyrene; vinyl halides such as vinylidene chloride and vinylidene fluoride; N such as N-phenylmaleimide and N-cyclohexylmaleimide -Substituted maleimides I can get lost. These may be used alone or in combination of two or more. Here, “(meth) acrylate” means acrylate or methacrylate.

  The polymer to be graft copolymerized with vinyl chloride is not particularly limited as long as vinyl chloride is graft-polymerized. For example, ethylene-vinyl acetate copolymer; ethylene-vinyl acetate-carbon monoxide copolymer; Ethylene-ethyl acrylate copolymer; ethylene-butyl acrylate-carbon monoxide copolymer; ethylene-methyl methacrylate copolymer; ethylene-propylene copolymer; acrylonitrile-butadiene copolymer; polyurethane; chlorinated polyethylene; And polypropylene. These may be used alone or in combination of two or more.

  The average degree of polymerization of the vinyl chloride resin is preferably in the range of 400 to 1000, and more preferably in the range of 600 to 800. If the average degree of polymerization of the vinyl chloride resin exceeds 1000, the solubility of the vinyl chloride resin in an organic solvent may be deteriorated. Conversely, if the average degree of polymerization of the vinyl chloride resin is less than 400, the adhesive strength of the solvent-based adhesive may be reduced.

  The solvent-based adhesive of the present invention includes at least an organic solvent having a boiling point of less than 100 ° C. as an organic solvent, and further includes an organic solvent having a boiling point of 100 ° C. or more as necessary.

  Examples of the organic solvent having a boiling point of less than 100 ° C include alcohol-based organic solvents such as methanol (boiling point 65 ° C), ethanol (boiling point 78 ° C), 2-propanol (boiling point 82 ° C), 1-propanol (boiling point 97 ° C). Ester organic solvents such as methyl acetate (boiling point 57 ° C) and ethyl acetate (boiling point 77 ° C); ketone organic solvents such as acetone (boiling point 56 ° C) and methyl ethyl ketone (boiling point 80 ° C); n-hexane (boiling point 68 ° C) ), Aliphatic hydrocarbon organic solvents such as cyclohexane (boiling point 81 ° C.); ether-based organic solvents such as tetrahydrofuran (boiling point 66 ° C.); and chlorinated organic solvents such as dichloromethane (boiling point 40 ° C.). These may be used alone or in combination of two or more. The organic solvent having a boiling point of less than 100 ° C. is selected from the group consisting of acetone, tetrahydrofuran, ethyl acetate, and methyl ethyl ketone in order to satisfy the Japan Water Works Association Standard JWWA S101. You may use together.

  Examples of the organic solvent having a boiling point of 100 ° C. or higher include ester organic solvents such as propyl acetate (boiling point 102 ° C.) and butyl acetate (boiling point 126 ° C.); toluene (boiling point 111 ° C.), xylene (boiling point 139 ° C.), etc. Aromatic hydrocarbon organic solvents; ketone organic solvents such as methyl isobutyl ketone (boiling point 116 ° C.) and cyclohexanone (boiling point 156 ° C.); amide organic solvents such as dimethylformamide (boiling point 153 ° C.); methyl cellosolve (boiling point 124 ° C.) ), Glycol ether organic solvents such as ethyl cellosolve (boiling point 135 ° C.), and the like. As the organic solvent having a boiling point of 100 ° C. or higher, cyclohexanone is preferable in order to satisfy Japan Water Works Association Standard JWWA S101. These may be used alone or in combination of two or more.

  The amount of the organic solvent is in the range of 400 to 650 parts by weight with respect to 100 parts by weight of the resin. When the amount of the organic solvent is less than 400 parts by weight, the viscosity of the solvent-based adhesive becomes too high, making it difficult to apply, or applying the coating thickness when bonding a rigid polyvinyl chloride pipe and a rigid polyvinyl chloride pipe joint. If the thickness becomes too thick, it becomes difficult to insert the rigid polyvinyl chloride pipe into the rigid polyvinyl chloride pipe joint. When the amount of the organic solvent exceeds 650 parts by weight, the viscosity of the solvent-based adhesive becomes too low, the applied solvent-based adhesive droops, or when the rigid polyvinyl chloride pipe and the rigid polyvinyl chloride pipe joint are bonded, If the coating thickness becomes too thin, the surface of the hard polyvinyl chloride pipe and hard polyvinyl chloride pipe joint to be bonded will not swell sufficiently, making it difficult to insert the hard polyvinyl chloride pipe into the hard polyvinyl chloride pipe joint. It becomes.

  The content of the organic solvent having a boiling point of 100 ° C. or higher in the organic solvent is in the range of 0 to 100 parts by weight, preferably in the range of 0 to 60 parts by weight. When the content of the organic solvent having a boiling point of 100 ° C. or higher exceeds 100 parts by weight, sufficient adhesive strength cannot be obtained by curing for a short time after the construction (for example, 2 hours), and water etc. There is a problem that the amount of organic matter leached into the soil increases.

  A pigment or dye may be added to the solvent-based adhesive of the present invention in order to color the solvent-based adhesive to improve workability during application and facilitate confirmation after bonding.

  As the pigment, fine particle titanium oxide is suitable. The particulate titanium oxide is a titanium oxide having a primary particle diameter of 0.01 to 0.1 μm obtained by hydrolysis or vapor phase oxidation of a titanium salt. The primary particle diameter of titanium oxide is preferably 0.02 to 0.07 μm. If the primary particle diameter of titanium oxide is less than 0.01 μm, the transparency may be high, and it may be difficult to determine the presence or absence of coating. When the primary particle diameter of titanium oxide exceeds 0.1 μm, titanium oxide may be precipitated. By setting the primary particle diameter of titanium oxide within the above range, even after storage for a long period of time, the titanium oxide exhibits a uniform white color without precipitating, and therefore the presence or absence of application of the solvent-based adhesive can be confirmed. Here, the primary particle diameter means the average particle diameter of the unit particles before the particles adhere to each other.

  The compounding amount of the particulate titanium oxide is preferably in the range of 0.1 to 5.0 parts by weight, and 0.5 to 3.0 parts by weight with respect to 100 parts by weight of the total amount of the resin and the organic solvent. More preferably within the range of parts. If the blending amount of the particulate titanium oxide is less than 0.1 parts by weight, the transparency of the solvent-based adhesive is increased, and it may be difficult to determine whether or not the solvent-based adhesive is applied. When the compounding amount of the particulate titanium oxide exceeds 5.0 parts by weight, the particulate titanium oxide is likely to precipitate.

  There are two types of crystal forms of titanium oxide, a rutile form and an anatase form, and any form of titanium oxide can be used. In addition, the titanium oxide may be subjected to surface treatment (for example, stearic acid treatment for imparting hydrophobicity, Si-Al treatment for imparting weather resistance, or the like), or not subjected to surface treatment. Can be used.

  Moreover, you may add a thickener to the solvent adhesive of this invention as solid components other than the said resin. Although it does not specifically limit as said thickener, For example, inorganic silicate, aluminum oxide, titanium oxide, calcium carbonate, zinc oxide, iron oxide, organic or inorganic bentonite etc. are mentioned. The addition amount of the thickener is preferably in the range of 1 to 15% by weight, and more preferably in the range of 2 to 15% by weight, based on the total amount of the solvent-based adhesive. When the addition amount of the thickener exceeds 15% by weight, the thixotropy of the solvent-based adhesive is lowered, and the workability may be lowered due to high viscosity. By making the addition amount of the thickener 1% by weight or more, the adhesive strength of the solvent-based adhesive can be greatly improved.

  Moreover, you may add a stabilizer, anti-aging agent, a filler, etc. to the solvent adhesive of this invention as needed other than the said component.

EXAMPLES Hereinafter, although an Example , a reference example, and a comparative example demonstrate this invention, this invention is not limited to this.

[ Reference Example 1]
For 100 parts by weight of polymethyl methacrylate having a weight average molecular weight of 280,000 as an acrylic resin (resin having a ratio of acrylic resin of 100% by weight), 244 parts by weight of tetrahydrofuran (boiling point 66 ° C.) as an organic solvent; Methyl ethyl ketone (boiling point 80 ° C.) 244 parts by weight (total amount of organic solvent is 488 parts by weight) was blended, and the resin was dissolved in the organic solvent to obtain a solvent-based adhesive.

[ Reference Example 2]
Reference Example 1 except that 185 parts by weight of tetrahydrofuran, 243 parts by weight of methyl ethyl ketone, and 60 parts by weight of cyclohexanone (boiling point 156 ° C.) were used as the organic solvent (the total amount of the organic solvent was kept at 488 parts by weight). Similarly, a solvent-based adhesive was obtained.

( Example )
As resin, instead of 100 parts by weight of polymethyl methacrylate, 15 parts by weight of polymethyl methacrylate having a weight average molecular weight of 280,000, and vinyl chloride-vinyl acetate copolymer (vinyl chloride 89% by weight and vinyl chloride resin) Reference example except that 11 wt% copolymer of vinyl acetate, average polymerization degree 750, weight average molecular weight about 40,000) mixture with 85 polymer parts (resin with acrylic resin ratio of 15 wt%) In the same manner as in Example 1, a solvent-based adhesive was obtained.

[Comparative Example 1] (Conventional product)
As a resin, instead of 100 parts by weight of polymethyl methacrylate, a vinyl chloride-vinyl acetate copolymer (a copolymer of 89% by weight vinyl chloride and 11% by weight vinyl acetate, an average degree of polymerization of 750, (Weight average molecular weight of about 40,000) 100 parts by weight were used, and 65 parts by weight of tetrahydrofuran, 210 parts by weight of methyl ethyl ketone, and 125 parts by weight of cyclohexanone were used as the organic solvent (the total amount of the organic solvent was changed to 400 parts by weight). Except for this, a solvent-based adhesive was obtained in the same manner as in Reference Example 1.

[Comparative Example 2]
Comparative Example, except that the amount of tetrahydrofuran was changed to 140 parts by weight, the amount of methyl ethyl ketone was changed to 200 parts by weight, and the amount of cyclohexanone was changed to 60 parts by weight (the total amount of the organic solvent remained 400 parts by weight). In the same manner as in Example 1, a solvent-based adhesive was obtained.

[Comparative Example 3]
As an organic solvent, a solvent was obtained in the same manner as in Reference Example 1 except that 76 parts by weight of tetrahydrofuran, 265 parts by weight of methyl ethyl ketone, and 147 parts by weight of cyclohexanone were used (the total amount of the organic solvent was kept at 488 parts by weight). A system adhesive was obtained.

[Comparative Example 4]
The solvent system was the same as in Reference Example 1 except that 130 parts by weight of tetrahydrofuran, 130 parts by weight of methyl ethyl ketone, and 130 parts by weight of cyclohexanone were used as the organic solvent (the total amount of the organic solvent was changed to 390 parts by weight). An adhesive was obtained.

[Comparative Example 5]
The solvent system was the same as in Reference Example 1 except that 265 parts by weight of tetrahydrofuran, 265 parts by weight of methyl ethyl ketone, and 147 parts by weight of cyclohexanone were used as the organic solvent (the total amount of the organic solvent was changed to 677 parts by weight). An adhesive was obtained.

[Evaluation]
For the solvent-based adhesives obtained in the above Examples , Reference Examples 1 and 2 and Comparative Examples 1 to 5, evaluation of the adhesive strength of the solvent-based adhesive by a hydraulic fracture test, solvent by a tensile shear test, by the following method Measurement of adhesive strength of the adhesive, evaluation of hygiene, evaluation of applicability, and evaluation of insertability were performed.

[Evaluation method of adhesive strength of solvent-based adhesives by hydraulic fracture test (applicant's original method)]
As shown in FIG. 1, impact resistant hard polyvinyl chloride pipe joint (hereinafter abbreviated as “HITS”) socket 1 having a nominal diameter of 20A (20 mm) and two impact resistant hards having a nominal diameter of 20A. A polyvinyl chloride tube (hereinafter abbreviated as “HIVP”) 2 is inserted and bonded with a solvent-based adhesive at two bonding locations 3 respectively, and cured for a predetermined time, whereby a HITS socket 1 and two HIVP2 A connecting tube 4 made of Here, the connection pipe 4 having a curing time of 2 hours (referred to as “curing time 2 hr product” in Table 2) is prepared by making the connection pipe 4 under three conditions of a curing time of 2 hours, 6 hours, and 24 hours, respectively. ), A connection tube 4 with a curing time of 6 hours (indicated as “product with a curing time of 6 hours” in Table 2), and a connection tube 4 with a curing time of 24 hours (in FIG. 2, “product with a curing time of 24 hours”). In FIG. 5, three types of connecting pipes 4, which are referred to as “conventional product 24 hr curing”, were produced.

  Next, one end of the connecting pipe 4 is sealed with a watertight jig 5, and a water pressure pump 7 is connected to the other end of the connecting pipe 4 in a constant temperature water bath 6 at 23 ° C. to gradually increase the water pressure in the connecting pipe 4. Then, it was confirmed whether destruction of the original pipe (HITS socket 1 and HIVP2) or removal of HIVP2 from the HITS socket 1 occurred. Then, the case where the original pipe is broken is evaluated as “original pipe broken” (the strength of the bonded portion is higher than the strength of the original pipe), and the case where the HIVP 2 is pulled out from the HITS socket 1 is “missed”. (The strength of the bonded portion was lower than the strength of the original tube).

[Measurement Method of Adhesive Strength of Solvent Adhesive by Tensile Shear Test (JIS K 6850 Test Method)]
The measurement of the adhesive strength of the solvent-based adhesive by the tensile shear test was performed according to the test method of JIS K 6850. That is, as shown in FIG. 2, two sheet-shaped test pieces 11 having a thickness of 3.0 mm, which were produced by sheeting HIVP having a nominal diameter of 20A by hot pressing, were partially overlapped and overlapped. A simple overlap test piece was prepared by adhering these parts with a solvent-based adhesive 12 and curing for a predetermined time. The dimension of the bonding surface (the dimension of the overlapped part) is 12.5 mm along the longitudinal direction of the test piece 11 and 25.0 mm along the width direction of the test piece 11 (bonding area 12.5 × 25.0 mm ² ), the amount of the solvent-based adhesive 12 was 0.1 g, and a load of 120 g was applied to the bonded portion during curing.

  Here, a simple overlap test piece having a curing time of 2 hours was prepared by preparing each of the simple overlap test pieces under three conditions of a curing time of 2 hours, 3 hours, and 24 hours (in Table 2, “curing time 2 hr”). ”), Simple overlay test piece with a curing time of 3 hours (indicated in Table 2 as“ curing time 3 hr product ”), and simple overlay test piece with a curing time of 24 hours (in Table 2,“ curing time ”). 3 types of simple superposition test pieces were prepared.

  Then, at 23 ° C., as shown in FIG. 1, one test piece 11 is pulled along the longitudinal direction at a tensile speed of 5 mm / min, and the load (maximum load) when the simple overlap test piece breaks is obtained. It was measured. Then, the adhesive strength (MPa) was calculated by dividing the measured maximum load by the adhesion area.

[Method for evaluating the hygiene of solvent-based adhesives]
As shown in FIG. 3, two HIVPs 2 with a nominal diameter of 20A are inserted into both ends of a HITS socket 1 with a nominal diameter of 20A, respectively, and bonded with a solvent-based adhesive at two bonding locations, respectively. One end of the HIVP 2 (the end opposite to the HITS socket 1 side) is bonded to a HITS valve socket 8 having a nominal diameter of 20A with a solvent-based adhesive at one bonding point 3 (the bonding point 3 is a total of the total points). (3 locations) By curing for 2 hours, an evaluation kit 9 (designated as “curing time 2 hr product” in Table 2) consisting of a HITS socket 1, a HITS bulb socket 8, and two HIVPs 2 was prepared. . However, only in the case of using the solvent-based adhesive of Comparative Example 1, except that the curing time was changed to 24 hours, the evaluation kit 9 was prepared in the same manner, whereby the evaluation kit 9 having a curing time of 24 hours (Table 2). In this case, a product having a curing time of 24 hours is indicated.

  Then, the inside of the evaluation kit 9 is filled with tap water, and both ends of the evaluation kit 9 are sealed with the watertight jig 5 so that the tap water is sealed inside the evaluation kit 9 (sealed) and kept in that state for 24 hours. After that, water in the evaluation kit 9 was collected, and the amount of TOC in the collected water was measured.

[Method for evaluating applicability and insertability]
The applicability and insertability were evaluated for the workability of adhesive bonding work using a solvent-based adhesive. That is, at an ambient temperature of 40 ° C., a solvent-based adhesive is applied to the outer peripheral surface of one end of the HIVP having a nominal diameter of 50A (50 mm) and the inner peripheral surface of the HITS receiving port having a nominal diameter of 50A. Adhesive joining work was performed in which the part was inserted and held and dried, and the applicability and insertability were evaluated sensitively. Regarding coating properties, when the viscosity of the solvent-based adhesive is too high and difficult to apply, it is considered "difficult to apply" (poor coating property), and the viscosity of the solvent-based adhesive is too low and the applied solvent-based adhesive drips. Was “dripping” (poor applicability), and “no problem” (excellent applicability) in other cases. Regarding the insertability, the case where the insertion of HITS into the HITS was hard and difficult to implement was defined as “difficult to insert” (poor insertability), and “no problem” (good insertability) in other cases.

The evaluation results and measurement results of the solvent-based adhesives obtained in Examples , Reference Examples 1 and 2 and Comparative Examples 1 to 5 are the same as those of the solvent-based adhesives in Examples , Reference Examples 1 and 2 and Comparative Examples 1 to 5. It shows in Table 3 with a composition.

The rise of the tensile shear strength of the solvent-based adhesives obtained in Examples , Reference Examples 1 and 2 and Comparative Examples 1 to 5 is shown in FIG. From the comparison between the examples in Table 3 and FIG. 4 and Reference Examples 1 and 2 and Comparative Example 2, the adhesive strength at the time of curing for 2 hours is improved by using a resin containing 15% by weight or more of an acrylic resin. I understand. Further, from the comparison between Reference Examples 1 and 2 and Comparative Examples 3 to 5 in Table 3 and FIG. 4, by setting the amount of the organic solvent having a boiling point of 100 ° C. or more within the range of 0 to 100 parts by weight, 2 hours It can be seen that the adhesive strength at the time of curing is significantly improved.

FIG. 5 shows a comparison of the amount of TOC measured by the sanitary evaluation method of the solvent-based adhesives obtained in Examples , Reference Examples 1 and 2 and Comparative Examples 1 to 5. Further, from the comparison between Reference Examples 1 and 2 and Comparative Examples 3 to 5 in Table 3 and FIG. 5, by setting the amount of the organic solvent having a boiling point of 100 ° C. or more within the range of 0 to 100 parts by weight, 2 hours It can be seen that the hygiene at the time of curing is significantly improved.

Moreover, from the comparison between Reference Examples 1 and 2 and Comparative Examples 4 and 5 in Table 3, it can be seen that the effectiveness is improved by setting the total amount of the organic solvent within the range of 400 to 650 parts by weight.

In addition, it has been confirmed that the solvent-based adhesive of Comparative Example 1, which is a conventional product, satisfies the standards of Japan Water Works Association Standard JWWA S101. Therefore, the solvent adhesives of Examples and Reference Examples 1 and 2 in which the adhesive strength and hygiene at a curing time of 2 hours are superior to the solvent adhesive of Comparative Example 1 are the standards of Japan Water Works Association Standard JWWA S101. It is considered to satisfy.

  The solvent-based adhesive of the present invention is suitable as an adhesive for rigid polyvinyl chloride pipes (particularly, hard polyvinyl chloride pipes for water supply), but it is a solvent-based adhesive for bonding various articles containing vinyl chloride resins. It can be used as an agent.

1 HITS socket 2 HIV
3 Bonding point 4 Connecting pipe 5 Watertight jig 6 Constant temperature water tank 7 Water pressure pump 8 HITS valve socket 9 Evaluation kit

Claims (3)

A solvent-based adhesive containing a resin and an organic solvent,
The amount of the organic solvent is in the range of 400 to 650 parts by weight with respect to 100 parts by weight of the resin,
The resin contains a vinyl chloride resin having a polymerization degree of 400 to 1000, and contains 10% by weight or more of an acrylic resin,
Content of the organic solvent whose boiling point is 100 degreeC or more in the said organic solvent exists in the range of 0-100 weight part, The solvent type adhesive agent characterized by the above-mentioned. The solvent-based adhesive according to claim 1,
A solvent-based adhesive, wherein the vinyl chloride resin is a copolymer of vinyl chloride and vinyl acetate . The solvent-based adhesive according to claim 1 or 2 ,
A solvent-based adhesive, characterized in that it is for rigid polyvinyl chloride pipes.

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