Water repellent for treating solids

Details Water repellent for treating solids Water repellent for treating solids

1999-11-23

2001-05-29

Dawson, Robert (Department: 1712)

Coating processes

With post-treatment of coating or coating material

Heating or drying

C008SDIG001, C106S287160, C528S025000, C528S032000, C526S279000, C525S100000

Reexamination Certificate

active

06238745

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to a water repellent for treating solids (hereinafter referred to simply as a water repellent) and more particularly relates to a water repellent capable of imparting a durable and robust water repellency to solid materials.
BACKGROUND OF THE INVENTION
Within the sphere of the silicone water repellents used on fibers and fiber-based products, Japanese Published Patent Application (Kokoku or Examined) Numbers Sho 51-9440 (9,440/1976) and Sho 53-4158 (4,158/1978) teach silicone water repellents comprising methylhydrogenpolysiloxane, an aromatic or aliphatic hydrocarbon solvent (e.g., toluene, xylene, n-hexane, n-heptane), and a curing catalyst such as a platinum compound or an organotin compound. However, these silicone water repellents require heating at temperatures from 100 to 180° C., which has a negative influence on production costs and which also limits the types of fibers and fiber-based products to which these water repellents can be applied.
In addition, fluoropolymers are known to have the ability to impart water repellency and staining resistance to solids and as a result are also frequently used in, for example, the leather and building material sectors and as surface treatment processing agents. These fluoropolymers are the polymers of a perfluoro group-functional or fluoroalkyl-functional polymerizable monomer or the copolymer of such a monomer with another polymerizable monomer.
When treating a solid such as a fiber-based product, leather, or building materials to impart water repellency thereto, the consuming public desires spray formulations to facilitate the application process. However, the efficient generation of water repellency by a spray process imposes various limitations on the composition of the water repellent.
Thus, the following prerequisites must be met: (1) the base or active ingredient of the water repellent must have an excellent affinity or compatibility with the propellant gas; (2) the base or active ingredient of the water repellent must dissolve in a homogeneous manner in the solvent in the water repellent; and (3) the water repellent, when sprayed on a solid, must readily wet the surface of the solid and must have a suitable infiltrability into the solid. When these conditions are satisfied, a uniform spray and an excellent water repellency and staining resistance are produced without the generation of powder ejection, fluffing, or whitening.
The consuming public also considers it of crucial import that spray-formulated water repellents be usable with a high level of safety and without the appearance of unpleasant odor. As far as these issues are concerned, the fluoropolymers referenced above are insoluble in low-toxicity alcohols such as ethanol, and the organic solvent used to dissolve the fluoropolymers must therefore be selected from among solvents such as ketones, e.g., acetone or methyl ethyl ketone, esters such as ethyl acetate, aliphatic hydrocarbons such as n-hexane and n-heptane, aromatic hydrocarbons such as toluene and xylene, and chlorinated hydrocarbons such as 1,1,1-trichloroethane and trichloroethylene.
Unfortunately, almost all of these solvents fail to satisfy any of the preceding prerequisites (1) to (3). In actuality the only solvent that can be used for the fluoropolymers is 1,1,1-trichloroethane. This solvent has, however, been implicated as a cause of depletion of the atmospheric ozone layer and its use is being increasingly restricted for purposes of global environmental protection. Thus, investigations have been carried out in pursuit of a solvent for the fluoropolymers that could replace 1,1,1-trichloroethane, but at present acceptable results have yet to be obtained.
The object of this invention is to provide a water repellent for treating solids that has the ability to impart a highly durable and robust water repellency to solids.
SUMMARY OF THE INVENTION
Vinyl-type polymers having a carbosiloxane dendrimer structure in side chain or pendant position (“pendant carbosiloxane dendrimer-functional vinyl-type polymers”) not only provide an excellent performance in terms of water repellency and staining resistance, but are also extremely favorable from the perspective of solving the above-referenced environmental problem because such copolymers are soluble in organic solvent composed mainly of an alcohol.
DETAILED DESCRIPTION OF THE INVENTION
This invention relates to a water repellent for treating solids whose base or active ingredient is a pendant carbosiloxane dendrimer-functional vinyl-type polymer. This invention further relates to a spray-formulated water repellent for treating solids that comprises 0.5 to 20 weight % pendant carbosiloxane dendrimer-functional vinyl-type polymer, 30 to 98.5 weight % organic solvent, and 1 to 50 weight % propellant gas.
The base or active ingredient in the water repellent of the invention is a pendant carbosiloxane dendrimer-functional vinyl-type polymer. The carbosiloxane dendrimer structure in this pendant carbosiloxane dendrimer-functional vinyl-type polymer denotes a high-molecular-weight group with a predictable and highly branched structure that elaborates radially from a single core. An example of a carbosiloxane dendrimer having such a structure is the highly branched siloxane-silalkylene copolymer taught in the specification of Japanese Patent Application Number Hei 9-171154 (171,154/1997).
The carbosiloxane dendrimer structure in the vinyl-type polymer in the water repellent preferably is a group with the following general formula.
Z is a divalent organic group, for example, an alkylene group, arylene group, aralkylene group, ester-containing divalent organic group, ether-containing divalent organic group, ketone-containing divalent organic group, or amide-containing divalent organic group, among which organic groups with the following structures are preferred.
R
9
represents C
1
to C
10
alkylene, for example, methylene, ethylene, propylene, and butylene with methylene and propylene being preferred. R
10
represents C
1
to C
10
alkyl, for example, methyl, ethyl, propyl, and butyl with methyl being preferred. R
11
represents C
1
to C
10
alkylene, for example, methylene, ethylene, propylene, and butylene with ethylene being preferred. The subscript d is an integer from 0 to 4, and e is 0 or 1.
R
1
is C
1
to C
10
alkyl or aryl. The alkyl encompassed by R
1
is exemplified by methyl, ethyl, propyl, butyl, pentyl, isopropyl, isobutyl, cyclopentyl, and cyclohexyl. The aryl encompassed by R
1
is exemplified by phenyl and naphthyl. Methyl and phenyl are preferred for R
1
, and methyl is particularly preferred. X
1
is the silylalkyl group with the following formula at i=1.
R
1
is defined as above. R
2
represents C
2
to C
10
alkylene and is exemplified by straight-chain alkylene such as ethylene, propylene, butylene, and hexylene, and by branched alkylene such as methylmethylene, methylethylene, 1-methylpentylene, and 1,4-dimethylbutylene. Ethylene, methylethylene, hexylene, 1-methylpentylene, and 1,4-dimethylbutylene are preferred for R
2
. R
3
in the preceding formula is C
1
to C
10
alkyl and is exemplified by methyl, ethyl, propyl, butyl, and isopropyl. The superscript i is an integer with a value from 1 to 10 that specifies the generation of said silylalkyl group, and a
i
is an integer from 0 to 3.
Preferred for use in the water repellent is a carbosiloxane dendrimer-functional vinyl-type polymer as afforded by the polymerization of
(A) 0 to 99.9 weight parts vinyl monomer
and
(B) 100 to 0.1 weight parts carbosiloxane dendrimer that contains a radically polymerizable organic group and has the following general formula.
Y is a radically polymerizable organic group. R
1
is C
1
to C
10
alkyl or aryl. The alkyl encompassed by R
1
is exemplified by methyl, ethyl, propyl, butyl, pentyl, isopropyl, isobutyl, cyclopentyl, and cyclohexyl. The aryl encompassed by R
1
is exemplified by phenyl and naphthyl. Methyl and phenyl are preferred for R
1
, and methyl is particularly preferred. X
1
is the silylal

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