JPH0119344B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a waterproof structure comprising a polyurethane resin waterproof material layer having a protective layer with excellent weather resistance. [Prior Art] Conventionally, coating film waterproofing has been widely used as a waterproofing method for buildings such as roofs and outer walls. A waterproof structure obtained by coating waterproofing is usually a multilayer structure. For example, there is first a thin primer layer on the surface of a substrate such as concrete or mortar, then an undercoat layer, then a topcoat layer, and in some cases a protective layer, also called a finishing layer, on the topcoat layer. The primer layer mainly functions to improve the adhesion between the base and the waterproof layer, the undercoat layer mainly functions as a buffer layer to prevent the waterproof layer from being destroyed due to cracks in the base, etc. Mainly responsible for waterproofing function. The undercoat layer and topcoat layer may be reinforced with a fiber sheet or the like. Further, an intermediate layer, particularly a heat insulating layer such as a foam sheet, may be provided between the substrate and the undercoat layer. As mentioned above, the waterproof material layer mainly consists of an overcoat layer and an undercoat layer, which are made of a highly elastic synthetic resin. For example, acrylic resins made of polymers of acrylic esters and methacrylic esters, synthetic rubbers such as chloroprene rubber,
Polyurethane resins are often used, and polyurethane resins containing or not containing tanol are most widely used. These synthetic resins usually have insufficient weather resistance, and deteriorate in a short period of time, resulting in a decrease in waterproof performance. Therefore,
A protective layer with high weather resistance is often provided on the surface of these synthetic resin layers. Alkyd paints and acrylic urethane paints are often used as materials for the protective layer. However, these materials are also usually 1~
Chyoking occurs after 3 years, and therefore it becomes necessary to scrape off the protective layer and apply a new protective layer every 1 to 3 years. In particular, waterproofing materials made of polyurethane resin tend to have weather resistance problems, and it is almost essential to provide a protective layer in polyurethane resin waterproofing materials installed outdoors. On the other hand, it is often a problem that the elasticity of the protective layer tends to decrease at low temperatures. Particularly in cold regions, the waterproof layer is easily damaged during the winter, and one of the reasons for this is that the elasticity of the protective layer decreases, making it more likely to cause cracks and scratches due to external stress. Therefore, the protective layer is required not only to have weather resistance but also to maintain elasticity at low temperatures. [Problems to be Solved by the Invention] In order to improve the weather resistance of the protective layer, it is necessary to develop a paint with high weather resistance. So-called fluororesin paints are known as paints with high weather resistance, but ordinary fluororesin paints have low elasticity and are not suitable as materials for forming protective layers that require high elasticity. Moreover, conventional acrylic urethane resins, which have relatively good weather resistance, are insufficient as protective layer forming materials that have high elasticity even at low temperatures. [Means for Solving the Problems] The present invention was made to solve the above-mentioned problems, and relates to a waterproof structure using a highly elastic fluorine-containing polyurethane resin paint as a material for the protective layer. The invention is as follows. Consisting of a waterproof layer provided on a substrate and having a polyurethane resin surface, and a fluorine-containing polyurethane resin protective layer that protects the polyurethane resin surface, the fluorine-containing polyurethane resin of the protective layer is
A waterproof structure comprising a fluorine-containing polyurethane resin obtained by reacting a fluoroolefin copolymer polyol with a hydroxyl value of about 160 or less, a high molecular weight polyol with a hydroxyl value of about 200 or less, and a polyisocyanate compound. The waterproof structure in the present invention has a waterproof material layer made of various highly elastic synthetic resin materials as an essential component as described above, but may also have a fiber sheet, a heat insulating material layer, etc. . The synthetic resin material may contain tar, carbon black, colorants, fillers, ultraviolet absorbers and light stabilizers, flame retardants, plasticizers, and other additive components. Further, the waterproof material layer may have a single layer structure or a multilayer structure, and in the latter case, the materials of each layer may be different. In addition, the waterproofing material is preferably a so-called coating film waterproofing material, which is formed by applying a curable liquid synthetic resin material, a synthetic resin emulsion or solution, or other liquid material, but is limited thereto. Instead, it may be a so-called sheet waterproof material formed by pasting a sheet or film of elastic synthetic resin or rubber. In the present invention, the surface of the waterproof material layer is made of polyurethane resin. That is, the uppermost layer of the waterproof material layer needs to be made of polyurethane resin. Compared to surfaces made of other synthetic resins, the surface of polyurethane resins has good compatibility with fluorine-containing polyurethane resins, and also has fluorine-containing polyurethane resins that can be cured at room temperature or at relatively low temperatures. Another advantage is that it can be applied to polyurethane resins that have relatively low heat resistance. Preferably, the synthetic resin material of the waterproofing layer includes all internal layers (e.g.
It is preferable that both the top coat layer and the undercoat layer are made of polyurethane resin. The protective layer that protects the surface of the waterproof material layer is made of a fluorine-containing polyurethane resin obtained by reacting a polyol having a fluorine atom, a polyol having no fluorine atom, and a polyisocyanate compound. Two or more of these polyols and polyisocyanate compounds can be used in combination, and other reactive raw material components can also be used if necessary. In addition, stabilizers such as ultraviolet absorbers, light stabilizers, and antioxidants, colorants, viscosity modifiers, leveling agents, and other auxiliary raw materials can also be blended with the fluorine-containing polyurethane resin. Further, these raw materials are usually used as a coating composition dissolved or dispersed in a solvent, and this coating composition is applied to the surface of the waterproofing agent layer and dried and hardened to form a protective layer. The fluoroolefin copolymer polyol, which is one of the essential raw material components, is a polyol containing a fluorine raw material and is an important factor for improving weather resistance. Several types of polyols with different hydroxyl values are known, but in order to obtain a fluorine-containing polyurethane resin with high elasticity, it is necessary to have a hydroxyl value of about 160 or less and a relatively low molecular weight per hydroxyl group. Must be a high polyol. In particular, the hydroxyl value is about 30 to 120, and even about 40.
~80 polyols are preferred. Further, this fluoroolefin copolymer polyol must be soluble in a solvent. Otherwise,
This is because a good coating composition cannot be obtained. The fluoroolefin copolymer polyols that can be dissolved in the above-mentioned solvents are basically known polyols. This polyol has a basic structure of a copolymer of a fluoroolefin such as tetrafluoroethylene or trifluorochloroethylene and a vinyl ether monomer, and by using a hydroxyl group-containing vinyl ether monomer as part or all of the vinyl ether monomer, hydroxyl groups are added to the copolymer. be introduced. The ratio of fluoroolefin units and vinyl ether monomer units in the fluoroolefin copolymer is preferably about 40 to 60 mol% for the former and about 60 to 40 mol% for the latter. Copolymers outside this ratio range and copolymers with a large ratio of units of the third type of monomer other than both types of monomers have reduced solvent solubility. Further, in the present invention, in order to lower the hydroxyl value, it is usually necessary to use a vinyl ether monomer having no hydroxyl group in combination with a vinyl ether monomer containing a hydroxyl group. As the hydroxyl group-containing vinyl ether monomer, hydroxyalkyl vinyl ether and hydroxycycloalkyl vinyl ether are preferable.
In particular, vinyl ethers having a hydroalkyl group having about 6 or less carbon atoms are preferred. Specifically, for example, 3-hydroxypropyl vinyl ether, 4
-Hydroxybutyl vinyl ether, 4-hydroxy-2-methylbutyl vinyl ether, etc. As the vinyl ether monomer having no hydroxyl group, vinyl ethers having an alkyl group or cycloalkyl group having 8 or less carbon atoms are preferred, such as ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, hexyl vinyl ether, and cyclohexyl vinyl ether. Further, fluorine-containing alkyl vinyl ethers such as 2,2,3,3-tetrafluoropropyl vinyl ether and other vinyl ether monomers can also be used. The intrinsic viscosity of fluoroolefin copolymer-based polyols (measured in tetrahydrofuran at 30°C) is approximately 0.05 to 2.0 dl/
g, particularly preferably 0.05 to 0.7 dl/g. If the intrinsic viscosity is too low, the mechanical strength of the fluorine-containing polyurethane resin will decrease, and if it is too high, it may cause difficulties in construction. The second polyol, a high molecular weight polyol with a hydroxyl value of about 200 or less, is necessary to increase the elasticity of the fluorine-containing polyurethane resin and maintain its elasticity at low temperatures. Too high a hydroxyl value causes a decrease in elasticity. On the other hand, if the hydroxyl value is too low, it may increase the viscosity of the paint composition and make it difficult to apply, so the lower limit of the hydroxyl value is approximately 30.
It is preferable that More preferably, about 40~
A polyol with a hydroxyl value of 160 is used,
In particular, polyols having a hydroxyl value of about 60 to 140 are preferred. The average number of hydroxyl groups per molecule of this polyol is suitably about 2 to 8, but if it is too high, the elasticity tends to decrease, so about 2 to 4 is preferred. Particularly preferred are polyols mainly composed of about 2 to 2.4 diols. Examples of this polyol include polyether polyols, polyester polyols, hydrocarbon copolymer polyols (for example, polybutadiene polyols), and acrylic polyols (for example, copolymers of acrylates or methacrylates having hydroxyalkyl groups and other acrylates or methacrylates). , polycarbonate polyol, etc. may be used.
Specifically, polyhydric alcohol, polyhydric phenol,
Polyether polyols obtained by adding ethylene oxide, propylene oxide, butylene oxide, and other alkylene oxides to polyfunctional initiators such as alkanolamines and polyamines, ring-opening polymers of tetrahydrofuran, and ring-opening polymers of tetrahydrofuran and alkylene oxide. Polyether polyols made of polyoxytetramethylene polyols, polybutadiene polyols made of butadiene and copolymers of it with acrylonitrile, styrene, etc., hydroxyalkyl (meth)acrylates and alkyl (meth)acrylates such as hydroxyethyl acrylate. There are acrylic polyols made of copolymers with and the like, polyester polyols such as polyethylene adipate diol and polybutylene adipate diol, and polycarbonate polyols such as poly(1,6-hexylene carbonate) diol. Particularly preferred high molecular weight polyols are polyether polyols, and polyether diols are particularly preferred. More preferred are polyoxypropylene diols or polyoxytetramethylene diols containing a high proportion of oxypropylene groups or oxytetramethylene groups (approximately 70% by weight or more). If the amount of the high molecular weight polyol used is too large, the weather resistance will be reduced, and if it is too small, the elasticity will be reduced. Therefore, the amount is about 5 parts by weight per 100 parts by weight of the fluoroolefin copolymer-based polymer.
~50 parts by weight, especially about 8 to 30 parts by weight are preferred. As the polyisocyanate compound that reacts with the polyols to form the polyurethane resin, compounds having two or more isocyanate groups or modified products thereof can be used. As a polyisocyanate compound. There are aliphatic, alicyclic, or aromatic polyisocyanate compounds. Aromatic polyisocyanate compounds having an isocyanate group directly bonded to an aromatic nucleus are called yellowing polyisocyanates, and it is known that polyurethane resins obtained using the same are susceptible to yellowing. Since the fluorine-containing polyurethane resin in the present invention is required to have weather resistance, the polyisocyanate compound is preferably a polyisocyanate other than yellowing polyisocyanate (non-yellowing polyisocyanate) or a modified product thereof. Examples of non-yellowing polyisocyanates include hexamethylene diisocyanate, octamethylene diisocyanate, lysine diisocyanate, other aliphatic polyisocyanates, isophorone diisocyanate, methylene bis(cyclohexyl isocyanate), bis(isocyanate methyl) cyclohexane, and other alicyclic polyisocyanates. , and xylylene diisocyanate, α,
Examples include α, α′, α′-tetramethylxylylene diisocyanate and other non-yellowing aromatic polyisocyanates. Furthermore, polymers and copolymers of vinyl monomers having isocyanate groups such as 2-isocyanate ethyl methacrylate can also be used. The polyisocyanate compound may be a modified product of these polyisocyanates,
Examples include prepolymer-type modified products modified with polyhydric alcohols such as trimethylolpropane, carbodiimide-modified products, urea-modified products, Biuretz-modified products, trimerization (isocyanurate)-modified products, and dimerization-modified products. The amount of the polyisocyanate compound to be used is as specified in 2 above.
About 0.4 to 1.2 per equivalent of the total of the seed polyols, or the total of 1 equivalent of the two types of polyols and optional raw material components such as the chain extender described below.
The equivalent amount is appropriate. If the equivalence ratio is greater than this,
This may cause a decrease in elasticity and surface performance, and if the amount is less than this, there is a risk of a decrease in mechanical strength. A more preferred equivalent ratio is about 0.7 to 1.0 equivalents. Fluorine-containing polyurethane resins are formed by mixing the above two types of polyols and polyisocyanate compounds, or by producing a prepolymer or quasi-prepolymer, adding a chain-preventing agent or a crosslinking agent thereto, and curing the mixture through a reaction. Ru. As the chain extender and crosslinking agent, low molecular weight polyols and polyamines are suitable. These can also be used together with the two polyols mentioned above. However, these low molecular weight compounds often reduce the elasticity of the fluorine-containing polyurethane resin and are not normally used. In the present invention, as described above, raw materials such as polyol and auxiliary raw materials are dissolved in a solvent, a polyisocyanate compound is added thereto, and a coating composition obtained is applied to the surface of the waterproof material layer at room temperature or at a low temperature. A protective layer is formed by drying and curing under heating (preferably about 60°C or less). The thickness of this protective layer is suitably about 10 μm or more; if it is thinner than this, it is difficult for the protective layer to fully exhibit its function. Furthermore, if the thickness is too large, the elasticity of the protective layer is likely to be insufficient. The thickness of the protective layer is preferably about 20-200μ. The waterproof structure of the present invention has excellent properties as a waterproof structure for a base made of an inorganic material such as concrete, mortar, or metal, particularly for a base exposed outdoors such as a roof or an outer wall. but,
The application is not limited to this, but it can be used as a waterproof structure constructed especially on the outdoor surface of a building or structure. Furthermore, the base material is not limited to inorganic materials, but may also be organic materials such as wood materials and plastic materials. EXAMPLES The present invention will be specifically explained below using Examples, but the present invention is not limited to these Examples. (Example) A coating composition was manufactured using the following raw materials. Coating composition fluoroolefin copolymer-based polyol ^*
100 parts by weight high molecular weight polyol (PTMG or PPG) ^**
10 parts by weight Xylene 165 parts by weight Toluene 165 parts by weight Colorant 59 parts by weight Modified polyisocyanate ^*** 22.5 parts by weight *Fluoroolefin copolymer polyol:
A copolymer of trifluorochloroethylene, ethyl vinyl ether, and 4-hydroxybutyl vinyl ether (mol% of each unit is 50, 40, and 10 in order), with a hydroxyl value of 57 and an intrinsic viscosity of 0.21 dl/g. **PTMG: Polyoxytetramethylene diol with a hydroxyl value of 110 PPG: Polyoxypropylene diol with a hydroxyl value of 110 **Modified polyisocyanate: Trimerized modified hexamethylene diisocyanate (NCO content
(21.3% by weight) Approximately 250g/ ^m2 of commercially available polyurethane primer was applied to the concrete substrate on the roof of the building.
After drying and curing, commercially available glass cloth was fixed with adhesive. Next, apply 2.5 kg/m ² of a commercially available polyurethane waterproofing material for undercoating and harden it, and then apply 2.5kg/m2 of a commercially available polyurethane waterproofing material for top coating on top of it.
Kg/m ² was applied and cured. After 24 hours, the above coating composition was further applied by roll coating in an amount of 250 g/m ² and cured. In order to evaluate the physical properties of the waterproof structure, the following tests were conducted. 1 container contains 400 g of the main ingredient of the polyurethane waterproofing material for top coating and 400 g of hardening agent.
g was accurately weighed and stirred slowly for 5 minutes using a metal spatula to avoid entraining bubbles. this mixture
600g was cast onto a 50cm square glass plate coated with a mold release agent.
It was smoothed with a rubber spatula to form a 2 mm thick layer. After standing at room temperature for 24 hours, the coating composition was
Apply by roll coating method to a thickness of 40μ, 20℃,
It was cured for 10 days under 60% humidity. Thereafter, the sheet was peeled off from the glass plate, and the following evaluation test was conducted.
Among the coating compositions, an example in which a composition containing PTMG was used was referred to as Test Example 1, and an example in which a composition containing PPG was used was referred to as Test Example 2. In addition, a sheet was prepared by the above method using the same coating composition except that no high molecular weight polyol was blended and the amount of modified polyisocyanate was 25% by weight. This example will be referred to as Comparative Example 1. Further, a sheet was prepared by the above method using a commercially available acrylic urethane paint for top coat of a waterproof material instead of the paint composition. This example will be referred to as Comparative Example 2. Using the above four types of sheets, the elongation at break was measured at 20°C and -20°C using a Tensilon tester (pulling speed: 500 mm/min). On the other hand, an accelerated weathering test was conducted on the coated surface using a Sunshine Weatherometer. After 3000 hours, the elongation at break was measured in the same manner at 20°C. The results of each test are shown in Table 1 below. Furthermore, after 500 hours, 1500 hours, and 300 hours in accelerated weathering tests.
The gloss retention rate of the coated surface after a period of time was measured. The results of each test are shown in Table 1 below. In addition, in Comparative Example 2, yoking had already occurred after 500 hours.

[Table] [Effects of the Invention] The protective layer material of the present invention not only has extremely high weather resistance, but also has high elasticity even at low temperatures, and has a better surface protection function than conventional materials for waterproof materials. It has extremely excellent properties.

Claims (1)

[Scope of Claims] 1. Consisting of a waterproof layer provided on a substrate and having a polyurethane resin surface, and a fluorine-containing polyurethane resin protective layer that protects the polyurethane resin surface, the protective layer is made of a fluorine-containing polyurethane resin. The resin is
A waterproof structure comprising a fluorine-containing polyurethane resin obtained by reacting a fluoroolefin copolymer polyol with a hydroxyl value of about 160 or less, a high molecular weight polyol with a hydroxyl value of about 200 or less, and a polyisocyanate compound. 2. The waterproof structure according to claim 1, wherein the protective layer has a thickness of about 20 to 200μ. 3. A fluoroolefin in which the fluoroolefin copolymer polyol is composed of tetrafluoroethylene or trifluorochloroethylene,
The waterproof structure according to claim 1, which is a copolymer of at least three types of monomers: a vinyl ether monomer containing a hydroxyl group and a vinyl ether monomer having no hydroxyl group.