JPS61288370A - Glass mat for storage battery - Google Patents

Abstract

PURPOSE:To increase the mechanical strength of the mat of a battery by using a binder made by adding alkaline material to the copolymer of a specific amount of N-alkylol acrylamide and/or N-alkyletherificated alkylol acrylamide. CONSTITUTION:The binder is made by adding alkaline material, in order to improve the adhesiveness to the glass fiber, to the copolymer emulsion or solution mainly composed of 5-25wt% of alpha,beta-monoethylenic unsaturated carboxylic acid, 0.5-15wt% of N-alkylol acrylamide and/or N-alkyletherificated alkylol acrylamide, 0.5-10wt% of unsaturated monoglycidil compound, and 50-95wt% of vinilic monomer excluding described above. Then the binder is adhered on the mat made of glass fiber, and by drying and solidifying the binder the mat for the storage battery can be completed.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a storage battery glass mat used as a storage battery separator. More specifically, it has good acid resistance, water resistance, electrolyte permeability, and especially high mechanical strength.
This invention relates to a glass mat for storage batteries that has excellent workability when assembling storage batteries.

<Conventional technology and its problems> In conventional storage battery glass mats, water-soluble substances such as starch and gelatin, or phenolic resins and acrylic resins are used as binders, and acrylic resins are particularly preferred. It has been nine times.

For example, Special Publication No. 48-27093, Special Publication No. 53-57
00, Japanese Patent Publication No. 57-26546, etc., 7-acrylic resin is described as a binder for glass fibers, but glass mats for storage batteries using these binders do not have sufficient mechanical strength, and it is difficult to use glass mats. Due to poor workability when installing between the electrode plates of a storage battery, and insufficient moisture resistance and acid resistance, the binder component may be eluted when it comes into contact with the sulfuric acid solution in the storage battery, causing the electrolyte to leak. It has disadvantages such as contamination, reduced bulk, and reduced pressure on the electrode plates, which shortens the life of the storage battery.

Means for Solving Problems〉 As a result of intensive research in view of the above situation, the present inventors have found that
It has been found that the above-mentioned drawbacks can be improved by using a binder made by adding an alkaline substance to a copolymer further containing a specific amount of N-alkylolacrylamide and/or N-alkyl etherified alkylolacrylamide as a component. This finding led to the completion of the present invention.

That is, the present invention provides: (a) α,β-monoethylenically unsaturated caldicic acid 5
-25% by weight, (b) N-alkylolacrylamide and/or N-alkyl etherified alkylolacrylamide 0.5-15% by weight, (c) Unsaturated monoglycidyl compound 0.5-10
Weight %, (d) Vinyl monomers other than the above 50~
The present invention provides a glass mat for a storage battery characterized by using a binder obtained by adding an alkaline substance to a copolymer containing 94% by weight as a main component.

Examples of the α,β-monoethylenically unsaturated cargonic acid (-) used in the present invention include acrylic acid, methacrylic acid,
Examples include itaconic acid, fumaric acid, maleic acid, and crotonic acid, with acrylic acid and methacrylic acid being particularly preferred. Although the reason is not clear, when itaconic acid is used as part of the acid component, that is, when itaconic acid is used in combination with another acid, preferably acrylic acid or methacrylic acid, a binder with particularly excellent adhesiveness can be obtained. This is preferable because it allows

The usage amounts of the above (&) ingredients are (a), (b),
When the total amount of components (c) and (d) is 100 wt. If the amount of component (a) used is less than 5% by weight, the mechanical strength of the glass mat will not be sufficient, and if it exceeds 25% by weight, the moisture absorption rate will increase and the moisture resistance will decrease, which is not preferable.

Examples of the N-alkylolacrylamide and/or N-alkyl etherified alkylolacrylamide (b) used in the present invention include N-methylolacrylamide, N-methoxymethylacrylamide, N-ethoxymethylacrylamide, N-butoxymethylacrylamide, etc. Among them, N-methylolacrylamide is preferred.

The amount of the component (b) used is in the range of 0.5 to 15% by weight, preferably 3 to 10% by weight; less than 5% is sufficient to improve the mechanical strength of the glass mat. Moreover, if it exceeds 10% by weight, no improvement in mechanical strength can be expected, which is not preferable.

Examples of the unsaturated glycidyl compound (c) used in the present invention include glycidyl methacrylate, glycidyl acrylate, allyl grindyl ether, and among them, glycidyl methacrylate is preferred.

The amount of the above component (c) to be used ranges from 0.5 to 10% by weight, preferably from 2 to 7% by weight; if it is less than 0.5% by weight, there is no improvement in mechanical strength; Exceeding this is not preferable because the mechanical strength will decrease.

Vinyl monomers other than components (a), (b), and (c) used in the present invention include (IL), (b), and (c).
Known monomers copolymerizable with each of the components, such as acrylic acid ester, methacrylic acid ester, styrene, vinyl acetate, itaconic acid ester, maleic acid ester, vinyl chloride, vinylidene chloride, butadiene, etc.
I can do it.

The usage amount of component (d) above is the essential component (a) e
(b) 50 to 94% by weight excluding the three components of e(c)
It is.

The copolymer used in the present invention can be produced by emulsion polymerization by a known and commonly used method using an anionic or nonionic emulsifier alone or in combination, or by using a medium such as water or alcohol. You can use any method such as solution polymerization! It is preferable to carry out emulsion polymerization using a known method.

The copolymer emulsion or solution obtained in this way is used as a binder for use in the present invention by adding an alkaline substance to improve its adhesion to glass fibers, and then this binder is applied to a mat made of glass fibers using a known method. It is attached by the following method and dried and solidified to form a glass mat for storage batteries.

It is preferable that the binder used here has a rating of 6 or more, and alkaline substances that volatilize during the drying process during glass mat production remain in the glass mat and reduce moisture resistance, water resistance, etc. This is preferable in that it does not. Examples of alkaline substances include ammonia (used as ammonium hydroxide), methylamine, dimethylamine,
Examples include trimethylamine, ethylamine, diethylamine, triethylamine, and the like.

When producing the glass mat of the present invention, casein and cornstarch, which have been conventionally used as a binder for glass mats, are used.1. It is also possible to use carboxymethylcellulose, polyvinyl alcohol, phenol resin, etc. together with the copolymer in an appropriate ratio.

<Effects of the Invention> Since the glass mat for storage batteries of the present invention has particularly excellent mechanical strength, there is almost no deterioration in workability due to fluffing or insufficient strength during battery assembly, which is seen in conventional glass mats. Also, it has excellent moisture resistance, so there is little loss of strength during storage, and it has good acid and water resistance, so the glass mat will not be attacked by the electrolyte, and the battery's performance can be maintained for a long time. It is.

<Example> The present invention will be specifically described below with reference to Examples and Comparative Examples. All parts and parts in examples are based on weight.

Examples 1 to 5 and Comparative Examples 1 to 5 In a 5-ton flask equipped with a stirring device, thermometer, nitrogen blowing device, reflux condenser, and dropping device, 147 parts of ion-exchanged water and ? 8 parts of ammonium lyoxyethylene nonylphenol ether sulfonate were charged, nitrogen was slowly blown in, and the temperature was raised to SO'C while stirring. 8
A solution of 0.5 parts of potassium persulfate dissolved in 3.3 parts of ion-exchanged water was charged at 0°C, and then 100 parts of a monomer mixture having the composition shown in Table 1 was added to the mixture at 80°C for 4 hours.
It dripped over time. After the addition was completed, the mixture was kept at 80° C. for another 2 hours, and then cooled to obtain a copolymer emulsion with a non-volatile content of 40.

Take 7.730 parts of this emul, add 170 parts of water, 2
A binder with a non-volatile content of 6% was obtained by adding 2 parts of aqueous ammonia.The viscosity and - of this binder are shown in Table 1.

The nonvolatile content concentration and viscosity of this binder were adjusted as appropriate so that the amount of binder adhered after drying was a predetermined amount (12%), and after that, glass fibers with a thickness of about 19 μm were intertwined vertically and horizontally and overlapped. It was impregnated into a glass mat with a thickness of 1.5 m and dried for 10 minutes in a constant temperature dryer at 160°C until the amount of binder attached was 1.
A 2-chi (88% glass mat) glass mattora for storage batteries was obtained.

The buckling strength, acid reduction rate, moisture absorption rate, and electrolyte permeability of the thus obtained glass mat for storage batteries were measured.
All of the glass mats for storage batteries of the present invention showed good results. The measurement results are shown in Table-1. The measurements were performed as follows.

Measurement method: Buckling strength: The yield strength is expressed as I/10vm when a glass mat specimen measuring 100 m in length and 10 m in width is compressed in the direction.

Acid resistance reduction rate: according to JIS C-2202,
Weight loss rate when immersed in dilute sulfuric acid with a specific gravity of 1.2,800 for 5 hours (→ 0) Moisture absorption rate: 48% in an atmosphere with a temperature of 25℃ and a relative humidity of 95℃
Moisture absorption rate when left for a period of time (→.

Permeability of electrolyte: When a 50IIIX50W specimen is gently placed horizontally on the surface of dilute sulfuric acid with a temperature of 25°C and a specific gravity of 1.2, the time required for the liquid to permeate the entire surface is measured and is 5 seconds. Less than 30 seconds is indicated by (○), 5 seconds or more but less than 30 seconds is indicated by (Δ), 30 seconds or more is indicated by gold (X).

Claims (1)

[Scope of Claims] (a) α,β-monoethylenically unsaturated carboxylic acid 5 to 2
5% by weight, (b) N-alkylolacrylamide and/or N
-Alkyl etherified alkylol acrylamide 0.
5-15% by weight, (c) 0.5-10% by weight of unsaturated monoglycidyl compound
(d) A glass mat for a storage battery, characterized in that it is made using a binder obtained by adding an alkaline substance to a copolymer whose main component is 50 to 94% by weight of a vinyl monomer other than the above. .