JPS59184760A - Binder for inorganic fiber - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a binder used in molding inorganic fibers such as asbestos and rock wool.

BACKGROUND ART A mixture of starch and its derivatives with a waterproofing agent has been used as a binder for molding inorganic fibers such as asbestos boards, asbestos slates, and rock wool boards. However, these binders do not have sufficient water resistance, and have the disadvantage that they tend to deform or rot in high-humidity environments, resulting in a markedly shortened product life.

In order to overcome the drawbacks mentioned above, the inventors of the present invention have conducted intensive research and found that asbestos, rock wool, etc. can be used as a binder when forming inorganic fibers by binding the main raw materials and mixing inorganic substances such as cement and clay as necessary. We have completed the present invention by discovering that when modified polyvinyl alcohol (hereinafter polyvinyl alcohol is abbreviated as PvA) having a silyl group in the molecule, the water resistance and strength of molded products are significantly increased.

The present invention will be explained in more detail below.

Modified P containing a silyl group in the molecule used in the present invention
VA may be of any type as long as it contains gyne in its molecule, but the silyl group contained in the molecule may be a reactive substitute such as an alkoxy group, an acyloxyl group, a silanol group which is a hydrolyzate of these, or a salt thereof. Those having groups are particularly preferably used.

Methods for producing such modified PVA include: ■ a method of introducing a silyl group into modified polyvinyl acetate containing P or a carboxyl group or a water M group by post-modification using a silylating agent; A method for saponifying a copolymer with a group-containing onfinically unsaturated monomer; One example is saponification. In the method of applying a silylating agent to PVA or modified polyvinyl acetate, for example, the silylating agent is added to an organic solvent that does not react with the silylating agent, such as benzene, toluene, xylene, hexane, heptane, ether, or acetone. Powdered PVA or the above-mentioned modified polyvinyl acetate is suspended in the solution with stirring, and the silylating agent and PVA or the modified polyvinyl acetate described above are dissolved at a temperature ranging from room temperature to the boiling point of the silylating agent. Silicon-containing modified P can be obtained by reacting polyvinyl acetate or by saponifying vinyl acetate units using an alkali catalyst or the like.
■, you can get to.

The silylating agents used in the post-modification include organohalogen purane such as trimethylchlorosilane, dimethyldichlorosilane, methyltrichlorosilane, diphenyldichlorosilane, and triethylfluorosilane, trimethylacetoxysilane, and dimethyldiacetoxysilane. Organosilicon esters, organoalcoquine silanes such as trimethylmethynesilane and dimethyldimethoxysilane, organosilanols such as trimethylsilanol and diethylcidine diol, aminoalkylsilanes such as N-aminoethylaminopropyltrimethoxysilane, trimethylsilicone isocyanate, etc. Examples include organone recon isocyanate. The rate of introduction of the silylating agent, that is, the degree of modification, can be arbitrarily adjusted by adjusting the amount of the silylating agent used and the reaction time. '1' The polymerization degree and saponification degree of the obtained silyl group-containing modified PVA can be arbitrarily adjusted by the polymerization degree and saponification degree of the PVA used or the polymerization degree and saponification reaction of the above-mentioned modified polyvinyl acetate. .

In the method of saponifying a copolymer of matavinyl ester and a silyl group-containing primary/finically unsaturated monomer, for example, a vinyl ester and a silyl group-containing olefinically unsaturated olomonomer are combined in an alcohol. is copolymerized with a radical initiator, and then an alcoholic solution of the copolymer (alkali or acid catalyst is added to saponify the copolymer to form a silyl group-containing modified P).
VA can be obtained. Vinyl esters used in the above method include vinyl acetate, vinyl propionate, vinyl formate, etc., but beer acetate is preferred from an economical standpoint. In addition, the silyl group-containing onfinically unsaturated monomer used in the above method has the following formula (
Examples include nylsilane represented by (2), and (meth)acrylamide-alkylsilane represented by (It).

R arm CH3=CH (CH2)n81 (R2)3m
(1) R4 RI n CH3=CR3-CN -R5- Si - (R2
)3-m(II )II where n is O-4, m is 0-2, R1 is an alkyl group having 1-5 carbon atoms (methyl, ethyl, etc.), R2 is carbon T1.
1 to 40 alkoxyl groups or acyloxyl groups (wherein the acyloxyl group or acyloxyl group may have an oxygen-containing substituent), R3 is a hydrogen atom or a methyl group, R4 is a hydrogen atom or a carbon number 1 ~5 alkyl group, t represents an alkylene group having 1 to 5 carbon atoms or a divalent organic residue in which chain element atoms are mutually bonded by oxygen or nitrogen. Note that R1 is the same monomer If there are two of them, R1 may be the same,
They may be different. Furthermore, when two or more R2s exist in the same monomer, R2s may be the same or different.

Specific examples of vinylsilanes represented by formula (1) include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris-(β-methyneethoxy)silane, vinyltriacetoxysilane, allyltrimethoxysilane, and allyltrimethoxysilane. Acetoxysilane, vinylmethyldimethoxysilane, vinyldimethylmethoxysilane, vinylmethyldiethoxysilane, vinyldimethylmethoxysilane, vinylmethyldiacetoxysilaneruacetoxysilane, vinylisobutyldimethoxysilane, vinyltriisopropoxysilane, vinyltributoxysilane , vinyl l-'J hequinroxy 7rane, vinylmethoxydihexyloxysilane, vinyldimethoxyoctyloxysilane, vinylmethoxydioleiroquine silane, vinyltrioctyloxysilane 7, vinylmethoxydioleiroquine silane, vinyldimethoxyoctyloxysilane Roxysilane, vinylmethoxydioleiroquine silane, vinyldimethoxyoctyloxysilane, and general formula %) (where R1 and m are the same as above, and X represents 1-20)
Examples include polyethylene glycolized vinylsilane represented by: Also, the formula C. TJ) (meta)
Specific examples of acrylamide-alkylsilanes include 3-(meth)acrylamido-propyltrimethoxysilane, 3-(meth)acrylamido-propyltriethoxysilane, 3-(meth)acrylamido-propyltri(β- Metkinetquin] Silane, 2-(meth)
Acrylamido-2-methylpropyltrimethoxysilane, 2-(meth)acrylamido-2-methylethyltrimethoxysilane, N-(2-(meth)acrylamidoethyl-aminopropyltrimethoxysilane, 3-
(meth)acrylamide-propyltriacetoxysilane, 2-(meth)acrylamide-ethyltrimethoxysilane, 1-(meth)acrylamide-propyltrimethoxysilane, 3-(meth)acrylamide-propylmethyldimethoxysilane, 3 -(meth)acrylamide-
Propyldimethylmethoxysilane, 3-(N-methyl=
(meth)acrylamide)-propyltrimethoxysilane, 3-((meth)acrylamide-methquin)-3-
Hydroxypropyltrimethoxysilane, :3-((
meth)acrylamide-methoxy)-propyltrimethoxysilane, dimethyl-3-(meth)acrylamide-
Propyl-3-(trimethinesilyl)-propylammonium chloride, dimethyl-2-(meth)acrylamide-2-methylpropyl-3-(1-I
J methoxysilyl)propylammonium chloride and the like.

In addition, in copolymerizing the vinyl ester and the silicon-containing olefinic unsaturated monomer in producing the modified PVA used in the present invention, the above-mentioned 2bj.
Other unsaturated monomers copolymerizable with monomers and monomers, such as styrene, alkyl vinyl ethers, vinyl versatate, (meth)acrylamide, ethylene,
Olefins such as propylene, α-hexane, and α-octene, unsaturated acids such as (meth)acrylic acid, crotonic acid, (anhydrous) maleic acid, fumaric acid, and itaconic acid, and their alkyl esters, alkali salts, and 2-acrylamide. -2
- Sulfonic acid-containing monomers such as methylpropanesulfonic acid and their alkali salts, trimethyl-2-, (1-(meth)acrylamido-1.1-methyl-3-(1-(meth)acrylamidopropyl) ammonium chloride) ,1
It is also possible to have a cationic monomer such as -vinyl-2-methylimidazole and its quaternized product present in a small proportion.

In a method for saponifying a polyvinyl ester having a silyl group at the end obtained by polymerizing a vinyl ester in the presence of a mercaptan having a truncated silyl group, for example, when vinyl ester is polymerized using a radical initiator, A mercaptan having a silyl group is added to the polymerization system V all at once, in parts, or continuously, so that the mercaptan having a silyl group is present in the polymerization system, and a polyvinyl ester having a silyl group at the terminal is produced by chain transfer to the mercaptan. After that, a modified PVA having a silyl group can be obtained by saponifying the polyvinyl ester by adding an alkali or acid catalyst to the alcohol solution of the polyvinyl ester.

As the mercaptan having a silyl group used in this method, 3-(trimethoxysilyl)-propyl mercaptan, 3-(triethoxysilyl)-propyl mercaptan, etc. can be used. In producing modified PVA by this method, it is also possible to include a small proportion of an unsaturated monomer copolymerizable with the vinyl ester used in method (2).

In the above-mentioned three production methods of modified PVA containing a silyl group in the molecule used in the present invention, a copolymer of a vinyl ester and an olefinic unsaturated monomer containing a silyl group is saponified. The method of saponifying a polyvinyl ester having a silyl group at the terminal obtained by polymerizing a vinyl ester in the presence of a mercaptan having a zolyl group has advantages in terms of ease of industrial production and homogeneity of the resulting modified PVA. Preferably used in

Modified PV containing silyl group used in the present invention
The content of silyl groups in A, the degree of saponification, or the degree of polymerization are appropriately selected depending on the purpose and are not particularly limited. The effect of the silyl group is exhibited even in a relatively small content, and the monomer unit containing the silyl group is usually selected from the range of 0, 1 to 10 mol, preferably 0.1 to 2.5 mol. The saponification degree is usually preferably in the range of 70 to 100 molar ratio. The degree of polymerization is usually selected from a range of 10 to 3,000.

When dissolving the above-mentioned modified PVA used in the present invention in water, the modified PVA is usually dispersed in water. In some cases, an alkali such as sodium hydroxide is added and heated while stirring to form a uniform water bath solution. can be obtained.

The binder of the present invention is usually used as a cooled aqueous solution when molding inorganic fibers, but in some cases it can also be added to inorganic fibers in powder form.

The binder of the present invention is sufficiently effective even when modified PVA is used alone, but it may also contain water-soluble inorganic substances such as water glass, pendulum sulfate, sodium aluminate, zirconium ammonium carbonate, clay, and talc. Water-insoluble inorganic substances such as carunium carbonate, calcium silicate, silica, and aluminum oxide may also be used. The amount of the binder added in the present invention is usually 05 to 30 parts, preferably 2 to 2 parts by weight, per 100 parts by weight of inorganic fibers.
Used in the range 0 parts.

The binder of the present invention is characterized by its ability to significantly increase the water resistance and strength of inorganic fiber molded products.

Although the reason why the binder of the present invention has the above-mentioned remarkable performance is not fully elucidated, the silyl group in the modified PVA that does not have a silyl group in the molecule used in the present invention is inorganic or modified. It is presumed that this is due to the high reactivity with the hydroxyl groups or silyl groups of the PVA shell, and these react with each other during molding to form a strong bond.

The present invention will be explained in more detail with reference to Examples below.
The present invention is not limited thereby. In addition, in the examples, unless otherwise specified, "department" and "department" are used.
represents the M quantity criterion.

Example 1 A silyl group obtained by saponifying a copolymer of vinyl trimethoquinone and vinyl acetate was set at the 3-position of vinyl sulfate, and the degree of saponification of the vinyl acetate unit was 98.
A 10% water bath solution was prepared by dissolving modified PVA having a molar ratio of 5 and a degree of polymerization of 1600 in water containing sodium hydroxide in a ratio of 2.5 to the modified PVA. Next, rock wool (density o1
6. To a slurry with a total inorganic fiber concentration of 4% containing 70 parts (fiber thickness 7 microns) and 30 parts of fully opened asbestos, add a 10% aqueous solution of the above modified P'VA to 1% total inorganic fiber.
00 parts so that the solid content of modified PVA is 7 parts, charged into a test pulper (JISP-8209), stirred and mixed, and further water added to the blade so that the total solid content concentration is 2%.
It became self-governing. Next, this slurry was put into the VC of a standard sheet machine (JIS P-8209), and water was added to make the slurry concentration 1.
Paper was made in the same manner as a normal paper making method. Then dehydrate,
Furthermore, '2 y with a sheet press (JIS P-8209)
4/ctA f After dehydration for 1 minute, it was dried for 3 minutes in a hot air dryer at 130°C. The obtained inorganic fiberboard was heated at 20℃6
The sample was left in a constant temperature and humidity chamber at 5% RH for 48 hours to be used as a measurement sample. The tsuboki of the sample for measurement was 125 f/m''. The water resistance and strength of this sample were measured. The results are shown in Table 1.

It can be seen from the first coating that the binder of the present invention has extremely high performance in terms of water resistance and strength.

Comparative Example 1 In place of the aqueous solution of modified PVA used in Example 1, oxidized starch (Nihon Shokuhin Ka I (illVls3800)
Melatane-formalin resin initial condensate (Sumitomo Chemical's Hasmine-Tsunjin 6) as a water-resistant agent for oxidized starch
13) Rice milled in the same manner as in Example 1 except that 2 parts were used is shown in Figure 3.

Examples 2 to 4 The same procedure as in Example 1 was carried out except that the following modified PVA aqueous solution was used in place of the modified PVA aqueous solution used in Example 1. The results are shown in Table 1. Both are water resistant,
It can be seen that the strength is good. Example 2: Contains 0.3 mole of silyl groups obtained by saponifying a copolymer of pinyltriacetogysilane and vinyl acetate as vinylan units, and saponification of vinyl acetate units. 1O% aqueous solution of i-type PVA with a polymerization degree of 200(1) and a polymerization degree of 990 molar ratio O Actual Example 3'
Dimethyl-2-acrylamido-2-methylpropyl-
A modified product containing 02 moles of silyl groups obtained by saponifying a copolymer of 3-trimethquine/tulpropylammonium chloride and vinyl acetate as acrylamide units, with a degree of saponification of vinyl acetate units of 93 moles and a degree of polymerization of 1750. 10% aqueous solution of PVA.

Example 4: 3-A modified carbon having a silyl group at the end obtained by polymerizing vinyl acetate in the presence of trimethoxysilylpropyl mercaptan contains 2 moles of silyl group units obtained by saponifying vinyl acetate, A 10% aqueous solution of modified PVA with a vinyl acetate unit resaponization degree of 99.0 molar and a polymerization degree of 50.

Table 1 1) Water resistance: Pour water into a 500mJ beaker and heat to 40°C.
While stirring at 300RPIvI, add 3 parts m x 3 of this medium.
The sample for measurement of crn was added, and the time (minutes) until the sample disintegrated and dispersed was measured.

2) Strength: The tearing length under normal conditions was measured according to JIS P-8113. The higher the tear length (Km), the higher the strength.

Claims (1)

[Claims] (12 Binder for inorganic fibers made of modified polyvinyl alcohol having a silyl group in the molecule 0 (2) Modified polyvinyl alcohol having a silyl group in the molecule has an olefinic property that cures the nisilyl group in the vinyl nysterte molecule The binder for inorganic fibers according to claim 1, which is a saponified product of a copolymer with an unsaturated monomer. (8) The olefinic unsaturated monomer having a silyl group in the molecule is vinyl alkoxysilane. The binder for inorganic fibers according to claim 2 is Binder for inorganic fibers according to item 2. (5) Polyvinyl ester having a silyl group at the end obtained by polymerizing a vinyl ester with a modified polyvinyl alcohol having a silyl group in the molecule in the presence of a mercaptan having a silyl group. The binder for inorganic fibers according to claim 2, which is a saponified product of.