JPH0222779B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a waterproofing method using a waterproof sheet used for roofing materials and the like. Conventional waterproofing methods for structures include asphalt waterproofing, mortar waterproofing, sheet waterproofing, and paint film waterproofing.Among these, sheet waterproofing has been widely adopted due to its ease of construction and excellent waterproof performance, and its construction results have increased significantly in recent years. It's growing. However, in the conventional sheet waterproofing method, an organic solvent-based chloroprene rubber or butyl rubber adhesive is used to bond the waterproof sheet to the base such as slab concrete, and the adhesive is applied to both the base and the waterproof sheet. It must be dried and then crimped.
Therefore, although it is said to be easier to construct than other waterproofing methods, it has the problems of deteriorating the working environment due to organic solvent emission and making the work somewhat complicated. From this point of view, the use of various water-based adhesives has been proposed, but these water-based adhesives still have various problems. For example, acrylic-based materials have insufficient alkali resistance and low-temperature adhesion, while synthetic rubber-based materials have shortcomings in low-temperature adhesion and durability. Waterproof sheets are often made of ethylene-propylene-diene terpolymer (hereinafter abbreviated as EPT) because of their durability, but this is difficult to adhere to due to its low polarity and hydrophobicity. It is something. Particularly for this EPT sheet, the fact is that the above-mentioned water-based adhesive does not provide sufficient adhesive strength even when applied to the base on one side, let alone on both sides. In addition, sheets with adhesive layers that have improved the adhesive properties of EPT sheets have recently been sold, but some acrylic emulsions may adhere under certain conditions, but after applying the emulsion, The reality is that when the degree of dryness increases, the tack is lost and crimping becomes impossible. The inventors of the present invention have conducted extensive research on a method of waterproofing by applying EPT to the base on one side using a waterproof sheet containing EPT as its main component without deteriorating the working environment. The inventors have discovered that using an adhesive composition containing a polymer dispersion as a main component satisfies the required performance and have arrived at the present invention. That is, the main component is an aqueous dispersion with an ethylene content of 5 to 50% by weight, a vinyl ester content of 50 to 95% by weight, and a glass transition temperature of -5°C to -40°C on a base consisting of slab concrete and special plywood. Water-based adhesive composition is applied on one side and dryness is 40-100%.
This is a waterproofing method that is characterized by attaching a waterproof sheet and then crimping a waterproof sheet. It is unique in that it is applied on one side and in a highly dry state, rather than on both sides, which is a complicated process. The dryness here refers to the apparent dryness of the adhesive, and as the adhesive layer dries after application, it changes from milky white to transparent, and the point at which it becomes transparent is defined as 100% dryness. The waterproof sheets used in the present invention include unvulcanized and vulcanized sheets made of EPT, butyl rubber, and mixtures thereof, polychloroprene sheets, chlorosulfonated polyethylene sheets, ethylene-vinyl acetate copolymer sheets, polyvinyl chloride sheets, etc. EPT, which has superior durability and strength, can be used, as well as sheets made from the synthetic polymers mentioned above and laminated with base fabric and other materials, and asphalt-based waterproof sheets where the base fabric is impregnated with asphalt.
A waterproof sheet containing as a main component is preferable. The ethylene content of the ethylene-vinyl ester copolymer that can be used in the present invention is 5 to 50% by weight. At 5% by weight or less, the glass transition temperature is -5°C.
If the amount is less than 50% by weight, the adhesion to EPT will decrease, and if it exceeds 50% by weight, the cohesive force will be extremely reduced and the high temperature adhesive strength will decrease. Also, the vinyl ester content is 50 to 95
% by weight. If it is less than 50% by weight, the cohesive force will decrease and the high temperature adhesive strength will decrease, and if it exceeds 95% by weight, the low temperature adhesive strength will decrease. Vinyl esters used in the present invention include vinyl esters of aliphatic carboxylic acids having 2 to 12 carbon atoms, such as vinyl acetate, vinyl propionate, vinyl laurate, vinyl tertiary carboxylates having an average of 10 carbon atoms (VeoVa10, Among them, vinyl acetate, vinyl propionate Veova 10, and a mixture thereof are particularly effective. Furthermore, as long as the above two components are within a specific range, it is also possible to use a component copolymerizable with these two components. Acrylic esters are particularly desirable, and butyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, etc. are suitable. Other copolymerizable unsaturated compounds include acrylic acid, methacrylic acid, maleic acid, fumaric acid,
Unsaturated carboxylic acids such as crotonic acid and itaconic acid,
Examples include methacrylic acid ester, N-vinylpyrrolidone, acrylamide, 2-hydroxyethyl acrylate, N-methylol acrylamide, glycidyl methacrylate, vinyl chloride, diallyl phthalate, triallyl cyanurate, ethylene glycol dimethacrylate, and the like. The aqueous dispersion used in the present invention is obtained by pressure polymerization in the presence of a surfactant or a protective colloid, but a protective colloid is preferable, and the protective colloid alone or in combination with a surfactant is effective. It is. Polyvinyl alcohol (hereinafter referred to as PVA) is the best protective colloid, with an average degree of polymerization of 100-4200 and a degree of saponification of 70-70.
In addition to using 100 mol% of partially or completely saponified products, unsaturated carboxylic acids such as acrylonitrile, acrylamide, crotonic acid, acrylic acid, methacrylic acid, maleic acid, itaconic acid, and their alkyl esters are used. So-called modified products, such as those copolymerized with vinyl acetate and then saponified, and those that are reacted with sulfuric acid, phosphoric acid, formalin, urea, maleic anhydride, etc. after producing PVA.
PVA or PVA derivatives can also be used. Protective colloids other than PVA include maleic anhydride-isobutylene copolymer, carboxylic acid-modified styrene copolymer, hydroxyethyl cellulose,
Hydroxypropyl cellulose etc. can be used.
As the surfactant, commercially available anionic surfactants, nonionic surfactants, and cationic surfactants are used. As the polymerization initiator, water-soluble inorganic peroxides or persulfates such as hydrogen peroxide and potassium persulfate, azo compounds, and the like are used. It is also possible to use redox initiators in combination with these and reducing agents.
In the polymerization method, the vinyl ester may be added all at once, in portions, or continuously. The glass transition temperature of the aqueous copolymer dispersion applied to the present invention is limited to -5° to -40°C. The value of the transition temperature varies depending on the measurement method, but here we will use torsional blade analysis (TBA,
(frequency 1Hz or less). Regarding TBA, see, for example, New Experimental Chemistry Course No. 19 edited by the Chemical Society of Japan.
Volume, page 904 (published by Maruzen, 1978). When the glass transition temperature is higher than -5°C, the adhesive strength at room temperature and at low temperature decreases, and when the glass transition temperature is lower than -40°C, the high temperature adhesive strength decreases, which is inappropriate. Especially −10° to −35
A range of 0.degree. C. is preferred. In the construction method of the present invention, the ethylene-vinyl ester copolymer aqueous dispersion is applied to a base made of slab concrete or special plywood, and the dryness level is 40.
It consists of taking an oven time until the dryness reaches ~100% and then crimping the tarpaulin sheet, but if the degree of dryness is
If it is less than 40%, there is a risk of adhesion failure if it rains immediately after construction, as it is difficult to absorb water.
It is necessary to dry at least 40% before laminating. The construction measures of the present invention are mainly applied to water-absorbing concrete, mortar, plywood, etc., but it can also be applied to non-water-absorbing substrates such as heat insulating materials and waterproof sheets. However, in that case, it is necessary to dry the adhesive layer 100% before laminating. The feature of the present invention is that waterproofing is carried out using a waterproof sheet whose main component is non-polar EPT, using a specific adhesive, and under specific conditions. That is,
Many common water-based adhesives have properties that can be used not only as adhesives but also as release agents for EPT.
The well-known aqueous dispersion of ethylene-vinyl ester copolymer also has low adhesion. However, an emulsion copolymer mainly composed of vinyl ester and ethylene with a glass transition temperature of -5 DEG C. to -40 DEG C. and a composition within a specific range exhibits significantly high adhesion to EPT, particularly improved low-temperature adhesive strength. Since this adhesive has ethylene as one of its main components, unlike rubber-based adhesives, oligomers are synthesized during polymerization, and tackifying substances are also automatically synthesized, resulting in improved adhesion to waterproof sheets and other substances. The properties are significantly improved and the workability is also improved. Furthermore, one of the features of the present invention is that it is non-polluting, water-based, does not require a primer on the substrate such as concrete or plywood, and can be bonded with one-sided coating, simplifying the installation process. Of course, it also has excellent cold resistance, heat resistance, and aging resistance. The adhesive composition used in the present invention may be mixed with an aqueous dispersion of other polymers, for example, vinyl acetate polymers, acrylic acid alkyl ester copolymers, olefin polymers, etc. Examples include aqueous dispersions of polymers, vinyl chloride polymers, styrene-butadiene copolymers, and the like. Furthermore, the adhesive of the present invention may contain other commonly used additives such as thickeners, tackifiers, plasticizers, antifoaming agents, pigments and isocyanate compounds, phenolic resins, melamine resins, urea resins, A crosslinking agent such as an epoxy compound may be mixed, but as in the case of mixing other aqueous polymer dispersions described above, the amount is limited to an amount that does not deteriorate the performance of the composition. Hereinafter, the present invention will be specifically explained with reference to Examples and Comparative Examples, but these examples are not intended to limit the present invention in any way. Note that "parts" and "%" in these examples are expressed on a weight basis unless otherwise specified. Example 1 In an autoclave with a stirrer and a jacket, 60.3 parts of ion-exchanged water, 0.2 parts of sodium bicarbonate, 0.5 parts of potassium persulfate, PVA (degree of saponification 88 mol%,
Polymerization degree 500) 2.6 parts, polyoxyethylene nonyl phenyl ether (number of moles of ethylene oxide added =
30) 1.3 parts were added and dissolved uniformly, and the ethylene pressure was increased to 50 Kg/cm ² and adjusted to 30±1°C. 0.06 parts of sodium metabisulfite and 0.26 parts of ion-exchanged water
1/6 of this solution was added to the autoclave. At the same time, 52.5 parts of vinyl acetate was continuously added over 11 hours, and a solution of 1.3 parts of polyoxyethylene nonyl phenyl ether (number of moles of ethylene oxide added = 30) dissolved in 33.7 parts of ion-exchanged water was successively added. Polymerization started immediately upon addition of vinyl acetate. During the polymerization, the remainder of the sodium metabisulfite solution was added in five portions. Incidentally, during the polymerization, a small amount of sample was appropriately sampled and the vinyl acetate concentration in the system was determined by bromine titration method, and it was found to be 1% or less in all cases. Also, the ethylene pressure is 50Kg/
cm ² and the temperature was kept constant at 30°±1°C until the end of the vinyl acetate addition. The resulting aqueous dispersion had good stability. The composition of the dispersion is shown in Table 1. The dispersion was applied to a sidewalk board (30cm x 30cm, JIS-A-
5304) at a coating weight of 300 g/m ² with a sponge roller, and the apparent dryness of the adhesive layer reached 70% after 30 minutes of open time. Next, an EPT waterproof sheet (manufactured by Toyo Tire & Rubber Co., Ltd.) was crimped, and after 3 days of curing (1) to (3), adhesive force measurement tests were conducted. (1) Normal peel strength The 90°C peel strength was measured using an autograph at a peeling rate of 100 mm/min at 20°C. (2) Water resistant peel strength Peel strength was measured according to (1) in a wet state after being immersed in tap water at 20°C for one week. (3) High temperature creep test Shear creep was measured at 70°C under a load of 200g. (Adhesive area: 25 mm x 25 mm) (4) Low-temperature adhesion EPT and sidewalk board were bonded at 5°C in the same manner as above, and after curing at 5°C for 3 days, the 90° peel strength was measured at 5°C. The results are shown in Table 2. As is clear from the table, the adhesive properties at low temperatures are good, and the normal state, water resistance strength, and high temperature creep properties are also excellent. Example 2 In the same autoclave as in Example, the average degree of polymerization was
1700, 4.5 parts of PVA with saponification degree of 88 mol% was dissolved in 70 parts of ion-exchanged water, and ethylene was added under pressure of 35 kg/ ^cm2 .
At 60°C, 76 parts of vinyl ester of a tertiary carboxylic acid having an average carbon number of 10 and vinyl acetate were continuously polymerized using a 1% aqueous solution of hydrogen peroxide and a 5% aqueous solution of Rongarit. The resulting aqueous dispersion was stable. The composition of the dispersion is shown in Table 1. Further, the peel strength measured in the same manner as in Example 1 is shown in Table 2. Example 3 The average degree of polymerization was carried out in the same autoclave as in Example 1.
1700, 2 parts of PVA with a saponification degree of 88 mol% and 2 parts of a nonionic activator (Nonipol 400, manufactured by Sanyo Chemical Co., Ltd.) at 70%
of acrylic acid, 60 parts ^of vinyl acetate,
22 parts of 2-ethylhexyl acrylate was continuously polymerized using a 2% aqueous solution of ammonium persulfate. The composition of the obtained aqueous dispersion is shown in Table 1, and the results of measurement of adhesive performance are shown in Table 2. Example 4 Aqueous dispersions with different monomer compositions were obtained using the same polymerization method as in Example 3. Its composition is shown in Table 1. A composition was prepared by adding and mixing 3 parts of dibutyl phthalate to 100 parts of the dispersion, and the adhesive performance was evaluated. The results are shown in Table 2. Example 5 Aqueous dispersions with different monomer compositions were obtained using the same polymerization method as in Example 3. Its composition is shown in Table 1. The adhesive performance of the dispersion is shown in Table 2. Example 6 Polymerization was carried out under the same conditions except that 5 parts of a nonionic surfactant (Nonipol 200) was used in place of 5 parts of PVA in Example 2. The composition of the obtained aqueous dispersion was
The adhesive performance of the dispersion is shown in Table 2. Example 7 In place of 5 parts of PVA in Example 2, 1 part of hydroxyethylcellulose and a nonionic activator (Nonipol) were used.
Polymerization was carried out under the same conditions except that 4 parts of 200) were used. The composition of the aqueous dispersion obtained is shown in Table 1, and the adhesive performance of the dispersion is shown in Table 2. Comparative Examples 1 to 4 Polymerization was carried out using the same polymerization method as in Examples, but with different monomer compositions. The composition of the aqueous dispersion obtained is shown in Table 1. Adhesion performance measured under the same conditions as Example 1 is shown in Table 2. As is clear from Table 2, the glass transition temperature is -
Those outside the range of 5℃ to -40℃, those with an ethylene content of 5% by weight or less, and those with a vinyl ester content of 50 to 95% by weight are normal, water resistant, low temperature peel strength and high temperature creep. It can be seen that one of the genders is low.

【table】

[Table] Comparative Example 5 and Example 8 Using the aqueous dispersion used in Example 2, an outdoor construction test was conducted under the following conditions. Base: Concrete frame coated with polymer cement mortar to a thickness of 5 mm Adherent material: EPT waterproof sheet [Toyo Rubber Co., Ltd. TS-S]
Sheet] Application amount: 300g/m ² (wet), adhesive area 1m x
The aqueous dispersion was applied to the 1 m base using a roller, and an open time was allowed. When the apparent dryness reached 10% and 60%, respectively, a waterproof sheet was attached. Next, assuming that it would rain immediately after construction, water was sprinkled on the waterproof sheet 3 hours after application of the aqueous dispersion. After 24 hours of watering, we made a 2.5mm-wide cut in the edge of the tarpaulin sheet and measured the adhesive strength between each tarpaulin sheet and the base.The results were 1.2Kg/25mm and 4.0Kg/25mm and 4.0, respectively, at 10% dryness and 60% dryness. Kg/25mm. If a waterproof sheet is attached to a substrate with relatively low water absorption, such as polymer-containing cement mortar, when the degree of dryness of the adhesive is low, there is a risk of poor adhesion due to rainfall after installation.

Claims (1)

[Claims] 1. An aqueous dispersion with an ethylene content of 5 to 50% by weight, a vinyl ester content of 50 to 95% by weight, and a glass transition temperature of -5° to -40°C is applied to a base made of concrete or plywood, etc. Apply a water-based adhesive as an ingredient,
A waterproofing method characterized by crimping a waterproof sheet at a dryness of 40 to 100%. 2. The waterproofing method according to claim 1, wherein the waterproof sheet is a sheet whose main component is ethylene-propylene-dien terpolymer.