JPH0224312B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a primer composition used for surface treatment of base materials in the construction of waterproof materials and the like. [Prior Art] When applying waterproofing materials, sealing materials, etc. to a base material, it is often necessary to treat the surface of the base material with a primer in advance. The purpose of primer treatment is to increase the adhesive strength between the base material and the waterproof material, and to prevent the formation of pinholes and the like. This primer treatment is usually an essential condition in coating film waterproofing, but primer treatment of the base material is also often performed in waterproofing such as asphalt waterproofing and sheet prevention. Furthermore, when applying a sealant, it is often necessary to treat the surface of the base material with a primer in advance to improve the adhesion between the sealant and the base material. Various primers are used depending on the base material and the type of waterproofing material or sealing material. For example, polyurethane-based primers, epoxy resin-based primers, rubber-based primers, etc. are used. [Problems to be Solved by the Invention] In addition to the above-mentioned improvement in adhesive strength, the primer coating film may be required to have low moisture permeability. When the base material is a water-containing base material such as concrete or mortar, if the water permeability of the primer film is high, the water that permeates through the primer film will have an adverse effect on the waterproof material. For example, reducing adhesive strength,
Causes blisters on waterproof materials, etc. Particularly in polyurethane-based waterproof coatings, the applied waterproofing material is easily affected by moisture, and it is thought that the occurrence of blisters is due to this moisture. Particularly during high temperature and high humidity in the summer, moisture evaporates from the base material to a great extent, resulting in frequent blisters, and this poses a problem in that construction must be carried out early in the morning or in the evening. [Means for Solving the Problems] The present invention has been made to solve the above-mentioned problems, and provides a primer composition that provides a primer coating film with particularly low moisture permeability. The present invention relates to a polyurethane-based primer composition particularly useful in waterproofing polyurethane-based coatings. A primer composition comprising an isocyanate group-terminated polyurethane prepolymer (A) obtained by reacting a polychloroprene polyol and optionally another active hydrogen-containing compound with a polyisocyanate compound and a vinylidene chloride polymer (B). . The present invention is a primer composition containing the above prepolymer (A) and vinylidene chloride polymer (B) as essential components, and is usually a solution composition further containing a solvent. This primer composition may further contain other components. For example, it may contain unreacted polyisocyanate compounds, fillers, colorants, urethanization catalysts, crosslinking agents, curing agents, viscosity modifiers, plasticizers, and the like. The primer composition of the present invention is usually a so-called one-component polyurethane primer, and is cured by moisture in the substrate or moisture in the air. However, the primer composition of the present invention may be a so-called two-component polyurethane primer, in which case a crosslinking agent or curing agent such as a polyol or polyamine is added immediately before application of the primer. The prepolymer (A) and vinylidene chloride polymer (B) will be explained below. The isocyanate group-terminated polyurethane prepolymer (A) is obtained by reacting a polychloroprene polyol or a polychloroprene polyol and another active hydrogen-containing compound with an excess equivalent of a polyisocyanate compound. The amount of the polyisocyanate compound to be used is not particularly limited as long as it is an excess equivalent, but usually at least about 1.3 equivalents are used, and about 1.5 to 10 equivalents are particularly preferred. Therefore, if the polyisocyanate compound is in large excess, unreacted polyisocyanate compound may remain, but this residual unreacted material is not particularly inconvenient. A more preferred amount of polyisocyanate compound to be used is about 2 to 8 equivalents. The prepolymer (A) is produced by adding a polyisocyanate compound to a polychloroprene polyol or a mixture thereof with another active hydrogen compound, or by adding the former to the latter. This reaction is usually carried out in a solvent. If necessary, the reaction may be carried out in the presence of a urethanization catalyst that promotes this reaction. Polychloroprene polyols are composed of chloroprene homopolymers or copolymers, and are polymers having an average of about two or more hydroxyl groups in one molecule. Hydroxyl groups are usually present at or near the molecular chain ends of polymers, and the average number of hydroxyl groups per molecule is often about 2 to 4. This polymer is an oligomeric polymer with a molecular weight of about 10,000 or less,
Normal ones have molecular weights in the range of about 1000 to 8000. This polychloroprene polyol is produced by radical polymerization or anionic polymerization of chloroprene or chloroprene and other monomers. for example,
It can be obtained by radical polymerization using a radical generator having a hydroxyl group or hydrogen peroxide, or by anionic polymerization using an alkali metal or its compound, and then reacting with epoxide, water, etc. to introduce a hydroxyl group. At present, there are very few commercially available polychloroprene polyols. The polychloroprene polyol used in the examples is commercially available from Denki Kagaku Kogyo Co., Ltd. under the trade name "LCR FH-50", which is chloroprene alone with a molecular weight of about 5000 to 6000 and an average number of hydroxyl groups of about 2.2 to 2.3. It is said to be a polymer. However, the chloroprene polyol is not limited to this, and chloroprene polyols made of other chloroprene homopolymers or chloroprene polyols made of copolymers mainly composed of chloroprene and other monomers can also be used. Other active hydrogen-containing compounds may be used in combination with the above chloroprene polyol. Other active hydrogen compounds include polyols, polyamines, alkanolamines, monools, and other compounds having at least one active hydrogen-containing functional group that can react with isocyanate groups such as hydroxyl groups and amino groups. In particular, it is suitable to use polyols having two or more alcoholic hydroxyl groups, such as polyether polyols, polydiene polyols, polyester polyols, polyhydric alcohols, and polyols such as di- or trialkanolamines. When these active hydrogen-containing compounds other than polychloroprene polyols are used in combination with polychloroprene polyols, they can be used in relatively large amounts as long as they provide a primer coating with low moisture permeability. The amount used is preferably about 60% by weight or less, particularly about 30% by weight or less based on the total amount including the polychloroprene polyol. As the active hydrogen-containing compound other than the polychloroprene polyol, polyols are preferred as described above, and hydrophobic polyols are particularly preferred. Preferred polyols are polyether polyols and polydiene polyols that do not contain oxyethylene groups or have a low proportion of oxyethylene groups. As the polyether polyol, polyoxyalkylene polyols containing oxypropylene groups, oxybutylene groups, oxytetramethylene groups, etc. are suitable, and polyoxypropylene polyols are particularly preferred. These polyoxyalkylene polyols may contain a small amount of oxyethylene groups, but as the proportion of oxyethylene groups increases, the hydrophilicity of the polyol increases. about
It is preferably 20% by weight or less. The number of hydroxyl groups in the polyether polyol is preferably about 2 to 8, especially about 2 to 4, and the hydroxyl value is about 20 to 800, especially about 100 to 4.
600 is preferred. Most preferably a hydroxyl value of about 200
~600 polyoxypropylene polyol. The above polyether polyol is usually produced by adding a cyclic ether such as alkylene oxide to a polyvalent initiator. Polyvalent initiators include polyhydric alcohols, polyhydric alkanolamines, polyhydric phenols, mono- or polyamines, such as water, ethylene glycol, propylene glycol, dipropylene glycol, 1.4
-butanediol, glycerin, trimethylolpropane, pentaerythritol, diglycerin, sorbitol, sucrose, monoethanolamine, diethanolamine, triethanolamine, bisphenol A, bisphenol S, ethylenediamine, tolylene diamine, and the like. Two or more of these may be used in combination. Particularly preferred initiators are polyhydric alcohols and polyhydric phenols.
As a cyclic ether, propylene oxide, 1.2
- or 2,3-butylene oxide, tetrahydrofuran, ethylene oxide, etc., with propylene oxide being particularly preferred. The polydiene polyol is a polyol obtained by polymerizing a diene other than chloroprene such as butadiene as a main monomer. Examples of copolymerizable monomers include acrylonitrile, styrene, acrylate, and methacrylate. Diene polyols are usually obtained by radical polymerization or anionic polymerization like polychloroprene polyols. Further, depending on the case, a hydrogenated polymer obtained by adding hydrogen to an unsaturated bond contained in a diene polymer can be used. The average number of hydroxyl groups per molecule of the polydiene polyol may be 2 or less (for example, 1.5), but it is usually about 2 or more, and about 1.8 to 4 is particularly preferred. In addition, its molecular weight is usually less than 10,000,
Those having a molecular weight of about 800 to 8000, especially about 1000 to 6000 are preferred. Primer coatings using this polyol have lower moisture permeability than polyether polyols, and therefore can be used in relatively large amounts. As active hydrogen-containing compounds other than polychloroprene-based polyols, in addition to the above-mentioned polyether-based polyols and polydiene-based polyols, low-molecular compounds such as polyhydric alcohols and alkanolamines, and other polymers having active hydrogen-containing functional groups as described above may be used. Compounds can be used. It goes without saying that two or more of these active hydrogen-containing compounds can be used in combination. The polyisocyanate compound is a compound having two or more isocyanate groups, and among these, aromatic polyisocyanate compounds are preferred. Other polyisocyanate compounds have low reactivity and are often uneconomical, and are generally not used unless yellowing is a problem. Examples of aromatic polyisocyanates include tolylene diisocyanate, diphenylmethane diisocyanate, polymethylene polyphenyl isocyanate,
These include naphthalene diisocyanate, xylylene diisocyanate, triphenylmethane triisocyanate, and modified products thereof. Examples of modified products include prepolymer-type modified products modified with polyhydric alcohols such as trimethylolpropane, trimerized products, dimerized urea-modified products, and other modified products. In addition, not only purified polyisocyanate compounds but also so-called crude polyisocyanate compounds can be used. Preferred polyisocyanate compounds are tolylene diisocyanate, diphenylmethane diisocyanate, and polymethylene polyphenyl isocyanate, and the latter two in particular provide a primer coating with lower water permeability than tolylene diisocyanate. Further, the crude product called crude diphenylmethane diisocyanate is diphenylmethane diisocyanate containing by-products such as polymethylene polyphenyl isocyanate, and is a preferred polyisocyanate compound from the economical point of view. The polychloroprene polyol and the polyisocyanate compound are usually reacted in a solvent. The solvent used is a solvent that is inert to active hydrogen-containing functional groups such as hydroxyl groups and isocyanate groups, and the resulting solution is mixed with vinylidene chloride polymers, etc., which will be described later, and then applied directly to the base material as a primer composition. Therefore, it is preferable to select it in consideration of drying properties and the like. Suitable solvents include hydrocarbon solvents, halogenated hydrocarbon solvents, ester solvents, Kent solvents, and ether solvents, with hydrocarbon solvents such as benzene, toluene, and xylene being particularly preferred. A prepolymer obtained by reacting a polychloroprene polyol, etc. with a polyisocyanate compound.
Next, a vinylidene chloride polymer and other additives are added to the solution (A) if necessary. However, the order of blending is not limited to this, and for example, the prepolymer (A) can be produced in a solvent containing a vinylidene chloride polymer. The vinylidene chloride polymer (B) is a polymer whose main component is vinylidene chloride, which is a homopolymer or copolymer of vinylidene chloride. Examples of monomers that can be copolymerized include vinyl chloride, acrylonitrile, acrylate, and methacrylate. Particularly preferred is a copolymer with vinyl chloride. Since the lower the amount of vinylidene chloride in the copolymer, the higher the water permeability, the proportion of vinylidene chloride in the copolymer is often at least about 80% by weight. The vinylidene chloride polymer can be blended into the prepolymer (A) in the form of a solution, dispersion, powder, etc., but an aqueous dispersion is not preferred because it brings moisture into the prepolymer composition. Usually, a solvent solution of vinylidene chloride polymer is used. Prepolymer (A) in the primer composition (including unreacted polyisocyanate compound, if any) and vinylidene chloride polymer (B)
The ratio is not particularly limited, and can be varied, for example, in a weight ratio of 5 to 95/95 to 5. However, the vinylidene chloride polymer is usually used in an amount of about 5 to 50% by weight, and preferably about 10 to 30% by weight, based on the total amount of both. Furthermore, the ratio of both of these in the primer composition can be changed depending on the purpose. Normally, a suitable concentration is used in consideration of workability. Workability is often mainly influenced by the viscosity of the primer composition. The viscosity of the primer composition of the present invention is not particularly limited, but it is generally preferably about 1000 centipoise (at 25°C) or less, particularly about 200 centipoise or less.
In addition, prepolymer (A), vinylidene chloride polymer
The ratio of the former two to the total of the three (B) and the solvent is preferably about 10 to 80% by weight, particularly about 20 to 60% by weight. The primer composition of the present invention is particularly suitable for treating hydrous substrates, but is not necessarily limited thereto. Hydrous base materials include concrete, mortar, slate, calcium silicate,
There are other inorganic substrates and organic substrates such as wood, which are usually porous. The primer composition of the present invention is suitable as a pre-treatment agent for base materials when waterproofing materials, sealing materials, etc. are applied onto these materials. In particular, as mentioned above, it is suitable as a pretreatment agent for a base material when a polyurethane-based coating film waterproofing agent is applied to an inorganic base material such as concrete or mortar. The primer composition may be applied to the substrate by, for example, a brush coating method, a spray method, a roller coating method, or the like. EXAMPLES The present invention will be specifically explained below with reference to Examples, but the present invention is not limited to these Examples. The raw materials used are as follows, and all amounts used are parts by weight. The viscosity is
Expressed in centipoise (cps) at 25℃,
[NCO content] represents the isocyanate group content. Polychloroprene polyol: Trade name "LCR FH-050" sold by Denki Kagaku Kogyo Co., Ltd. Polybutadiene polyol: Trade name "R-45HT" sold by Idemitsu Petrochemical Co., Ltd., polybutadiene diol with a molecular weight of about 2800. Polyether polyol: Hydroxyl value obtained by adding propylene oxide to glycerin
400 polyoxypropylene triol. PAPI-20: Polymethylene polyphenyl isocyanate having an average of about 3.0 isocyanate groups per molecule; sold by Kasei Upjiyon Co., Ltd. PAPI-135: Polymethylene polyphenyl isocyanate having an average of about 2.7 isocyanate groups per molecule; sold by Kasei Upjiyon Co., Ltd. Vinylidene chloride resin liquid: A solvent solution of vinylidene chloride-vinyl chloride copolymer at a concentration of about 40-50% by weight. [Example] Example 1 261 parts of polychloroprene polyol, 503 parts of xylene, and 119 parts by weight of PAPI-20 were charged into a glass reaction vessel, and heated to 90°C under nitrogen gas purge.
The mixture was stirred for 4 hours to obtain a brown homogeneous transparent liquid with an NCO content of about 3.4% by weight. After cooling this to 60°C, 117 parts of vinylidene chloride resin solution was added and stirred for 20 minutes.
A brown homogeneous transparent liquid with an NCO content of about 3.1% by weight and a viscosity of 40 cps was obtained. This liquid is hereinafter referred to as Primer A. Example 2 Example 1 using 248 parts of polychloroprene polyol, 570 parts of xylene, and 182 parts of PAPI-20
A prepolymer liquid having an NCO content of about 4.6% by weight was obtained by reacting in the same manner as above. To this, 176 parts of vinylidene chloride resin solution was added and stirred, and the NCO content was approximately 3.9% by weight.
A primer composition with a viscosity of 30 cps was obtained. This will be referred to as Primer B hereinafter. Example 3 After reacting in the same manner as in Example 1 using 300 parts of polychloroprene polyol, 576 parts of xylene, and 135 parts of PAPI-135, 500 ppm of stannous octoate was added with stirring, and the mixture was heated at 90°C for 300 parts.
A primer solution having an NCO content of about 3.1% by weight was obtained by reacting for a period of time. Add vinylidene chloride resin solution 178 to this
of NCO content and viscosity of about 2.8% by weight.
A primer solution of 55 cps was obtained. This will be referred to as Primer C hereinafter. Example 4 A prepolymer solution was produced in the same manner as in Example 1 using 250 parts of polychloroprene polyol, 24 parts of polyether polyol, 604 parts of xylene, and 182 parts of PAPI-20, and 187 parts of vinylidene chloride resin solution was added to this. Add and stir until the NCO content is approx.
A primer solution of 3.6% by weight and a viscosity of 45 cps was obtained.
Hereinafter, this will be referred to as Primer D. Example 5 Polychloroprene polyol 150 parts, polybutadiene polyol 150 parts, xylene 551 parts,
A prepolymer solution was produced by reacting 126 parts of PAPI-20 at 60°C for 3 hours, followed by adding 171 parts of a vinylidene chloride resin solution and stirring to obtain an NCO content of approx.
A primer solution of 2.8% by weight and a viscosity of 70 cps was obtained.
This will be referred to as Primer E hereinafter. Evaluation Test An evaluation test was conducted using Primers A to E produced in the above examples and the following primers. Primer F: A commercially available one-component polyurethane primer solution containing a prepolymer made from tolylene diisocyanate and polyoxypropylene polyol. Primer G: Commercially available one-component epoxy resin primer solution. Primer H: Polyurethane prepolymer-containing solution prepared in Example 1 and before adding the vinylidene chloride resin solution. Evaluation method: 85g/ ^m2 of primer on a 12cm diameter shear
(as the resin content) and 25℃, 45% so that the primer film thickness is 80μm.
The sample was cured in DH for 7 days. The moisture permeability of the primer film is
Measured by cup method according to JISZO208. That is, the inside of the moisture-permeable cup was sealed with a primer film, kept dry with _CaCl2 , and the cup was heated for 40 minutes.
The moisture permeability was defined as the amount (g) of water vapor that passed through the primer film surface in 24 hours after being left in a constant temperature and humidity chamber at 90% DH at 90° C. per 1 m ² of the primer film. Moisture permeability was calculated using the following formula. The results are shown below.
Shown in the table. Moisture permeability (g/ ^m2・24hr)=240×m/t・s s; Moisture permeable area ( ^cm2 ) t; Total time of the last two weighing intervals during which the test was conducted (hr) m ;Total mass increase in the last two weight intervals tested (mg)

【table】

[Table] [Effects of the Invention] The primer coating film obtained using the primer composition of the present invention not only has good adhesion to waterproof materials, etc., but also has particularly low moisture permeability, which prevents waterproofing caused by moisture permeation. It has a remarkable effect on reducing the occurrence of blisters in wood. Therefore, it is excellent as a substrate pre-treatment when applying a polyurethane waterproofing material to a water-containing substrate such as concrete, mortar, or slate.

Claims (1)

[Scope of Claims] 1. An isocyanate-terminated polyurethane prepolymer (A) and a vinylidene chloride polymer (B) obtained by reacting a polychloroprene polyol and, if necessary, another active hydrogen-containing compound with a polyisocyanate compound. A primer composition comprising. 2. The composition according to claim 1, wherein the polyisocyanate compound consists of polymethylene polyphenyl isocyanate and/or diphenylmethane diisocyanate. 3. The composition according to claim 1, wherein the other active hydrogen-containing compound is a polyether polyol and/or a polydiene polyol. 4. The composition according to claim 1, wherein the polyisocyanate compound is used in an amount of about 1.5 to 10 equivalents per 1 equivalent in total of the polychloroprene polyol and other active hydrogen compounds. 5 Isocyanate-terminated polyurethane polymer (A)
[However, if unreacted polyisocyanate compound exists, it is included] and vinylidene chloride polymer (B)
The composition of claim 1, comprising about 5 to 50% by weight.