JPS6354752B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a non-foaming water-curable urethane waterproofing material. Conventionally, urethane-based waterproofing materials have been commonly used as waterproofing materials for buildings, along with asphalt, sheets, and the like. As a urethane-based waterproofing material, there is a known waterproofing material made by combining a urethane prepolymer component having an isocyanate group at the end and a curing agent component containing active hydrogen such as polyol or polyamine. is mixed and applied to the building at the time of use. Urethane prepolymers are generally made from polyols and polyisocyanates at a reaction temperature of 50~
A product obtained by reacting at 100℃ at OH/NCO=1/2 (molar ratio).Polyols include polyester polyols, polyether polyols, acrylic polyols, tall oil derivatives, castor oil derivatives, and other hydrous acid group compounds. is used. As the polyisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, etc. are generally used. It is said that the residual amount of free isocyanate groups (-NCO%) is preferably 2 to 7% by weight. Polyols and methylenebisorthochloroaniline (abbreviated as MOCA) are commonly used as active hydrogen compounds. Coatings cured with polyols have lower tensile strength and tear strength than those cured with polyamines, so a large amount of carbon black is used as a reinforcing material to compensate for these weaknesses. However, in this case, only a black product can be obtained, and it also has the disadvantage that its strength is significantly reduced at high temperatures and its weather resistance is poor. on the other hand,
Although coatings cured with MOCA exhibit excellent physical properties, they are suspected of being carcinogenic, making them undesirable in terms of occupational safety and health.Although amines are being considered as a substitute for MOCA, they are highly reactive with isocyanate groups and are difficult to work with. The reality is that it has not been put into practical use due to its inferior performance. Furthermore, a method of curing using water as an active hydrogen compound is also known. in this case,
Although this is not preferable because it generates carbon dioxide gas and causes foaming, it is possible to produce non-foamed urethane by using carbon dioxide absorbents such as calcium oxide, magnesium oxide, slaked lime, and cement. Even when cured with water and a polyurethane prepolymer obtained by reacting commonly known polypropylene polyol with tolylene diisocyanate, thermal stability, weather resistance, physical properties, etc. are improved compared to polyol-cured systems, but the results are sufficiently satisfactory. The reality was that they were not getting it. In view of the above points, the present invention provides a urethane waterproofing material that is safe and has excellent thermal stability and weather resistance. That is, the present invention provides a urethane prepolymer with an isocyanate group content of 2 to 7% by weight obtained by reacting a polyol and a polyisocyanate,
water or polyether polyol as curing agent,
In urethane-based waterproofing materials that combine coal tar, oil tar, process oil, petroleum resin, and/or lubricating oil mixtures produced from these as dispersion media, and carbon dioxide gas absorbers when water is used as a hardening agent,
Furthermore, a urethane waterproofing material made by dissolving pitch in a dispersion medium [However, when water is used as the above-mentioned hardening agent, tolylene diisocyanate is used as the urethane prepolymer, and 5 to 20 mol% of the general tolylene diisocyanate is used. formula (However, R is an alkylene group having 2 to 3 carbon atoms,
n and m are 0 or positive integers, and 2<n+m
It is. A urethane prepolymer obtained by reacting a compound represented by ) with a polypropylene polyol is not used. ]. In the present invention, the urethane prepolymer has an isocyanate group (-NCO) content of 2 to 7% by weight,
In particular, it is preferable to use 3 to 6% by weight.
If the isocyanate group content is less than 2% by weight, the physical properties of the coating film tend to deteriorate, and if it exceeds 7% by weight, carbon dioxide cannot be absorbed sufficiently and only a foamed coating film is obtained, which tends to impair its function as a waterproof layer. It is in. The above urethane prepolymer is obtained by reacting a polyol and a polyisocyanate. Polyols include polyester polyols, acrylic polyols, tall oil derivatives, castor oil derivatives, and other hydrous acid group compounds, and polyisocyanates include tolylene diisocyanate,
Examples include diphenylmethane diisocyanate and hexamethylene diisocyanate. As the curing agent, a polyether polyol whose main raw material is water or propylene oxide is used. When using water as a hardening agent, a carbon dioxide absorbent is used to prevent foaming. Carbon dioxide absorbents include alkaline earth metal compounds such as calcium oxide and magnesium oxide, alkaline earth metal compounds such as calcium hydroxide and magnesium hydroxide, cement containing these, and alkali metal halogen compounds that react with carbon dioxide gas. Compounds that produce carbonates can be used. Pitch is dissolved in the dispersion medium. Pitch includes coal tar pitch, petroleum pitch, wood pitch, etc., and can be divided into general pitch and coke pitch. General-purpose pitches usually have soft pitches (softening point 50 to 60℃), medium pitches (softening points 60 to 60℃), and medium pitches (softening points 60 to 60℃).
75℃), hard pitch (softening point 90℃ or higher, JIS K)
2471, it is classified as 75℃ or higher). Among these, coal tar pitch is the most representative. In the present invention, hard pitch among coal tar pitches is particularly preferred. Further, as the dispersion medium, coal tar, oil tar, process oil, petroleum resin, and/or a lubricating oil mixture manufactured from these are used. The pitch is preferably dissolved in an amount of 20 to 70% by weight based on the total amount of the dispersion medium and pitch, and when water is used as a hardening agent, it is particularly preferably 40% by weight or less. It is preferable that the curing agent, the dispersion medium, and the carbon dioxide absorbent used if necessary be mixed in advance and used as a component containing the curing agent. In this case, the composition of components including a curing agent is preferably 3 to 20 parts by weight of the curing agent, 5 to 50 parts by weight of a dispersion medium dissolved in pitch, and 5 to 50 parts by weight when using a carbon dioxide absorbent. filler and carbon black,
A pigment such as titanium white may be added, and a dispersant may be added to improve the dispersibility of the hardening agent.
Furthermore, anti-aging agents, antioxidants, organic salts such as lead, tin, manganese, etc., amines, etc. can also be added. In these cases, it is preferable to add it in advance to the component containing the curing agent. The urethane waterproofing material of the present invention has a urethane prepolymer component of 25 to 50% by weight and a curing agent containing component of 50 to 50% by weight.
It is mixed before use to a concentration of 75% by weight and applied to areas where there is a risk of water permeation, such as concrete surfaces and mortar surfaces of buildings. Next, examples of the present invention will be shown. (1) According to the formulation shown in Table 1, after pre-mixing, knead with three rolls, and the components (A-1) containing a curing agent.
(A-6) was obtained.

【table】

[Table] (2) Urethane prepolymers were obtained by reacting the raw materials and formulations shown in Table 2 at 60 to 100°C for 8 hours in a nitrogen atmosphere. Its properties are shown in Table 1. This is called (B-1).

[Table] Product names of Seito Atsushi Kagaku Co., Ltd.
Examples 1 to 3 and Comparative Examples 1 to 3 Components (A-1) to (A
-6) and the urethane prepolymer (B-1) in a weight ratio of 1:1 or 2:1, and the physical properties of the obtained sheet were measured according to JIS A 6021 and are shown in Table 3. In Table 3, when comparing Comparative Example (1) and Example (1) in which pitch was dissolved in the dispersion medium, the change rate of tensile strength and the untreated -20℃, heat treatment and ultraviolet treatment The rate of change in tear strength at -20°C is particularly smaller in Example (1). Comparing Comparative Example (2) and Example (2) in which pitch was dissolved in the dispersion medium, the change in tensile strength at -20°C without treatment, heat treatment and ultraviolet treatment, and -20 The rate of change in tear strength in °C is much smaller in Example (2). moreover,
Comparative example (3) and an example in which pitch was dissolved in the dispersion medium
Comparing Example (3), the rate of change in tensile strength at -20°C without treatment and the rate of change in tensile strength after ultraviolet treatment are particularly smaller in Example (3). In addition, the elongation is JIS A for both Examples and Comparative Examples.
6021 standards. It is clear that when pitch is dissolved in a dispersion medium as described above, the rate of change due to temperature changes, ultraviolet treatment, and heat treatment is small and stable.

【table】

[Table] The urethane-based waterproofing material of the present invention can be used in harsh environments by using a dispersion medium in which pitch is dissolved.
It is possible to form a coating film waterproof layer that is stable against (temperature changes and ultraviolet irradiation).

Claims (1)

[Claims] 1. A urethane prepolymer with an isocyanate group content of 2 to 7% by weight obtained by reacting a polyol and a polyisocyanate, water or a polyether polyol as a curing agent, coal tar, oil tar, as a dispersion medium, In urethane-based waterproofing materials that combine process oils, petroleum resins and/or lubricating oil-based mixtures made from these, and carbon dioxide absorbers when water is used as a hardening agent,
Furthermore, a urethane waterproofing material made by dissolving pitch in a dispersion medium [However, when water is used as the above-mentioned hardening agent, tolylene diisocyanate is used as the urethane prepolymer, and 5 to 20 mol% of the general tolylene diisocyanate is used. formula (However, R is an alkylene group having 2 to 3 carbon atoms,
n and m are 0 or positive integers, and 2<n+m
It is. A urethane prepolymer obtained by reacting a compound represented by ) with a polypropylene polyol is not used. ].