JPH0362837A - Waterproofing sheet - Google Patents

Abstract

PURPOSE:To obtain a waterproofing sheet having improved tearing strength without deteriorating the characteristic flexibility of rubber by using a rubber composition composed of an ethylene-alpha-olefin copolymer rubber and/or butyl rubber and a specific modified ethylene copolymer. CONSTITUTION:The objective waterproofing sheet is produced by using a composition containing (A) 75-95wt.% of a rubber consisting of (A1) an ethylene-alpha- olefin copolymer rubber composed of ethylene and one or more kinds of monomers selected from alpha-olefins and non-conjugated dienes and/or (A2) a copolymer rubber of isobutylene and isoprene and having an isoprene content of 0.5-10wt.%, (B) 5-25wt.% of a copolymer composed of (B1) 70-95wt.% of ethylene. (B2) 4-25wt.% of an alpha,beta-unsaturated carboxylic acid alkyl ester (preferably ethyl acrylate, n-butyl acrylate or methyl methacrylate) and (B3) 1-5wt.% of maleic anhydride and preferably (C) a petroleum-based hydrocarbon resin, etc.

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to a waterproof sheet with excellent tear strength.

(1) <Conventional technology> Asphalt construction method, waterproofing construction method for civil engineering works such as waterproof sheet construction method for building rooftops, rivers, ponds, etc.
and sheet waterproofing methods are used. The asphalt waterproofing method is the most commonly used construction method, but it has several drawbacks: ■ It involves the risk of fire as it is a thermal method, ■ It is time-consuming because it requires a multi-layer finish, ■ The weather resistance and aging resistance of asphalt, It has disadvantages such as poor cold resistance and ability to follow the substrate, and difficulty in detecting and repairing water leakage points, and recently sheet waterproofing methods have been on the rise.

The sheet waterproofing method uses ethylene propylene non-conjugated diene copolymer rubber sheets, ethylene propylene non-conjugated diene copolymer rubber sheets, butyl rubber mixture rubber sheets, or polyvinyl chloride sheets, etc., at the construction site. A waterproof layer is formed by adhesion or fusing.

Performance conditions required for sheet materials include not only the ability to function as a waterproof sheet, but also the ability to not tear under tension during construction. In the case of the former rubber sheet (2), although it satisfies many of the performance requirements for a waterproof sheet, problems may occur during construction due to its low tear strength. In the case of the latter polyvinyl chloride sheet, it is weather resistant, cold resistant, and resistant.

<Problems to be Solved by the Invention> An object of the present invention is to provide a rubber sheet that has improved tear strength, which is a problem with conventional waterproof sheets, without impairing workability or other physical properties.

Means for Solving the Problems> The present inventors have conducted extensive studies to solve the above-mentioned problems with rubber waterproof sheets, and have arrived at the present invention. That is, the present invention provides 75 to 95% by weight of ethylene α-olefin copolymer rubber, butyl rubber, or a blend of ethylene d-olefin copolymer rubber and butyl rubber, as well as ethylene, α, β
- Modified material comprising unsaturated carboxylic acid alkyl ester and maleic anhydride (8) The present invention relates to a waterproof sheet characterized by using a rubber composition comprising 5 to 25% by weight of a tyrene copolymer.

Generally, a method of blending thermoplastic resins such as polyethylene and polyethylene-vinyl acetate copolymer is known as a means of improving the tear strength of rubber compositions, but the method of blending these thermoplastic resins is The resin discovered by the invention does not show any significant improvement in tear strength, and at the same time, the hardness and modulus of the vulcanized rubber increase, impairing workability during construction.

According to Japanese Patent Publication No. 62-502047, a modified ethylene copolymer consisting of ethylene, α, β-unsaturated carboxylic acid alkyl ester, and maleic anhydride is added to ethylene d-olefin copolymer rubber for the purpose of increasing hardness. However, like the thermoplastic resins mentioned above, depending on the usage, the hardness may increase and workability may decrease, which is contrary to the purpose of the present invention.

According to the present invention, it is possible to obtain a rubber composition that provides a rubber sheet with significantly improved tear strength without impairing processability or other physical properties (4).

That is, the present inventors discovered that ethylene α with a limited composition,
It has been found that a blend of the above rubber and a modified ethylene copolymer consisting of β-unsaturated carboxylic acid alkyl ester and maleic anhydride is a composition with improved tear strength without losing the flexibility characteristic of rubber. Ta.

In the present invention, (A) ethylene d-olefin copolymer rubber means a copolymer consisting of ethylene, one or more d-olefins, and non-conjugated diene, and the d-olefins include propylene, 1-butene, 1 -pentene, l-
Examples include hexene. Examples of non-conjugated dienes include dicyclopentadiene, ethylidene norbornene, p, 1.
Examples include 4-hexadiene, methyltetrahydroindene, methylnorbornene, and the like.

In the present invention, butyl rubber refers to a copolymer rubber of isobutylene and isoprene, and the content of isoprene is
0.5 to 10% by weight.

(5) In the present invention, (B) modified ethylene copolymer refers to 70 to 95% by weight of ethylene, 4 to 25% by weight of α,β-unsaturated carboxylic acid alkyl ester, and 1 to 1% of maleic anhydride.
It is a copolymer consisting of 5% by weight.

The α,β-unsaturated carboxylic acid alkyl ester is an unsaturated carboxylic acid having 8 to 8 carbon atoms, such as acrylic acid,
Alkyl esters such as methacrylic acid, specific examples include ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, isobutyl acrylate, methyl methacrylate, and methacrylic acid. These include ethyl, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, t-butyl methacrylate, and isobutyl methacrylate, and among these, ethyl acrylate, n-butyl acrylate, and methyl methacrylate. is preferred. The reason for limiting the ethylene content to 70 to 95% by weight is that below this range, the tear strength of the vulcanized rubber sheet does not improve (6), and above this range, the same improvement as when polyethylene is added occurs. This is because while only an effect can be seen, the hardness and modulus increase significantly.

In the present invention, especially when flexibility is required, petroleum hydrocarbon resins such as aliphatic hydrocarbon resins, coumaron/indene resins, phenol/formaldehyde resins, polyterpene resins, rosin esters, process oils, etc. are used. By appropriately blending, it is possible to maintain tear strength while controlling hardness and modulus within the optimum range.

For waterproof sheet applications, it is desirable to use petroleum-based hydrocarbon resins, coumaron-indene resins, phenol-formaldehyde resins, polyterpene resins, and rosin esters in order not to reduce adhesion.

In addition, the amount of modified ethylene copolymer (B) added is 5 to 25%.
The reason why it is limited to % by weight is that below this range, the improvement in tear strength is insufficient, and above this range, the improvement in tear strength reaches a plateau and the physical properties of the vulcanized rubber composition deteriorate. It is.

In the present invention, carbon (7) known in the rubber industry, reinforcing agents such as black and silica, coupling agents, fillers such as talc, clay, calcium carbonate, diatomaceous earth, mica, paraffin oil, naphthenic oil, etc. , aromatic oils, softeners such as submersibles, plasticizers, zinc white, stearic acid, vulcanization accelerators, vulcanizing agents, peroxides, etc. can be added. Moreover, various processing aids, pigments, etc. can be added as necessary. Furthermore, various heat-resistant stabilizers, weather-resistant stabilizers, anti-aging agents, antioxidants, flame retardants, etc. can be added due to the nature of its use as a waterproof sheet.

<Example> Hereinafter, the present invention will be specifically explained with reference to Examples.

BR type Banbury mixer according to the recipe shown in Table 1.
After kneading the mixture using an open roll, a vulcanizing agent and a vulcanization accelerator were added. 2Nn from the obtained unvulcanized rubber composition
A thick press sheet was prepared.

Table 2 shows the modified ethylene copolymers used.

Table 8 summarizes the physical properties (20°C) of the vulcanized rubber sheet.

As can be seen from Example and Comparative Example 5, when the modified ethylene copolymer discovered by the present invention is mixed (8), the tear strength is greatly improved. On the other hand, in Comparative Examples 2 to 4 in which other general-purpose resins were mixed, almost no improvement in tear strength was observed.

Further, there is also a large difference in tear strength between Example 6.7 and Comparative Example 6.7 for ethylene-propylene copolymer rubber/butyl rubber blends and butyl rubber.

Table 4 also shows the physical properties at temperatures of -20 and 60°C.

Table 5.6 shows formulation examples in which an aliphatic hydrocarbon resin, which is widely used as an adhesion improver and a plasticizer, is added, and the physical properties of the vulcanizate. According to this, modified ethylene copolymers (1) and (2) with a high ethylene content can also impart flexibility without reducing tear strength.

In other words, the modified ethylene copolymer added in the present invention essentially improves tear strength, and by using an appropriate formulation, flexibility can be controlled without impairing tear strength. .

Table-1 Formulation example *11 Vulcanization accelerator manufactured by Sumitomo Chemical ■ Table 1 (Continued) Formulation example Table 2 Characteristics of modified ethylene copolymers ■～■ Table 8 Vulcanized rubber physical properties (JIS K-6801) Table 4 Vulcanized rubber physical properties (18) Table 5 Compounding example table 6 Vulcanized rubber physical properties (14 completed) Procedural amendment (voluntary) July 1990/, 3rd 1, Case indication 1999 Patent application No. 199740 2. Name of the invention Tarpaulin sheet 3. Relationship with the case of the person making the amendment Patent applicant address 4-5-33 Kitahama, Chuo-ku, Osaka Name
(209) Sumitomo Chemical Co., Ltd. Representative Mori
Hero 4, Agent 5, Detailed description of the invention in the specification subject to amendment.

6. Contents of amendment (1) "Ethylene α-olefin" on page 1, line 16 of the specification is amended to "ethylene-α-olefin".

(2) "Ethylene α-olefin" on page 1, line 17 of the specification is corrected to "ethylene-α-olefin".

(3) "Ethylene α-olefin" on page 8, No. 12 of the specification is corrected to "ethylene-α-olefin".

(4) After "This is because it is inferior." on page 1, line 19 of the specification: r When producing a waterproof sheet in the present invention, the method of mixing the modified ethylene copolymer (B) and its method are not limited. For example, a mixture of ethylene-α-olefin copolymer rubber (A) and modified ethylene copolymer (B) may be used as a raw material in the production stage of ethylene-α-olefin copolymer rubber (A), or Ethylene-α in a kneader
- A waterproof sheet may be manufactured using a composition obtained by blending only the olefin copolymer rubber (A) and the modified ethylene copolymer (B) as a raw material.

that's all (2 complete) hand Continued Supplementary Positive book (spontaneous) October 3θ, 1990 1゜ Display of incidents 1999 Patent Application No. 199740 2゜ name of invention tarpaulin 3゜ person who makes corrections Relationship with the incident

Claims (2)

[Claims] (1) (A) Ethylene-α-olefin copolymer rubber, butyl rubber, or a blend thereof 75 to 95% by weight
and (B) 5 to 25% by weight of a modified ethylene copolymer made of ethylene, α,β-unsaturated carboxylic acid alkyl ester, and maleic anhydride. (2) The modified ethylene copolymer has ethylene of 70 to 95%
Weight %, α,β-unsaturated carboxylic acid alkyl ester 4
The waterproof sheet according to claim 1, which is a copolymer comprising ~25% by weight of maleic anhydride and 1-5% by weight of maleic anhydride.