Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Reexamination Certificate
2001-09-25
2003-08-26
Lipman, Bernard (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
C525S124000
Reexamination Certificate
active
06610775
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a water and oil repellent composition and a process for its production. The water and oil repellent composition of the present invention is a composition which imparts excellent water and oil repellency to an object to be treated, and particularly, it is capable of imparting excellent water and oil repellency to polyamide type fibers of a pale color type such as white color. Further, the water and oil repellent composition of the present invention is capable of imparting excellent heavy rain durability to an object to be treated.
PRIOR ART
Heretofore, to impart water and oil repellency to a fiber including a polyamide type fiber or a fiber fabric, a fluorine type water and oil repellent containing a fluoropolymer having polymerized units of a (meth)acrylate having a R
f
group, has been employed. However, the durability of the water and oil repellency of a fiber or a fiber fabric treated with such a conventional fluorine type water and oil repellent, has been inadequate, and there has been a problem that the water and oil repellent performance decreases by e.g. washing.
To solve such a problem, (1) a fluorine type water and oil repellent having a trimethylol melamine or an organic amine incorporated (JP-A-54-133486, JP-A-56-165072, JP-A-5-272060, etc.), (2) a fluorine type water and oil repellent having a polyfunctional blocked isocyanate urethane compound incorporated (JP-A-58-208473, JP-A-2-92985, etc.), and (3) a fluorine type water and oil repellent having an aminoplast resin and a polyfunctional blocked isocyanate urethane compound incorporated, have, for example, been proposed.
The fluoropolymers in the water and oil repellents of the above (1) to (3) contain polymerized units of a polymerizable monomer having active hydrogen atoms. Specifically, they contain polymerized units of e.g. N-methylol acrylamide, 2-hydroxyethyl (meth)acrylate or 2-hydroxy-3-chloropropyl (meth)acrylate. However, the durability of the conventional water and oil repellents shown in (1) to (3) was inadequate, and particularly, there was a problem that they were poor in washing durability. Further, such a problem was distinctly observed when they were applied to polyamide type fibers or fiber fabrics.
Further, (4) a method of pretreatment with a polyhydric phenol compound, followed by treatment with a fluorine type water and oil repellent (JP-A-58-46176), and (5) a method of pretreatment with a low condensate of sulfonated phenol formaldehyde, followed by treatment with a fluorine type water and oil repellent and an aminoplast resin (JP-A-1-221576), have been proposed. However, also with the objects treated by the methods of (4) and (5), washing durability was inadequate, and there was a problem that the hand of the treated objects tended to be coarse. Further, there was a problem that when treated by the methods of (4) and (5), the treated products tended to be colored, whereby there was a problem that they could not be applied to fibers of a pale color type.
The present invention has been made to solve the above problems. The present inventors have studied the causes as to why the conventional fluorine type water and oil repellents were not able to provide adequate performance. As a result, they have found that even if the fluoropolymer which is the effective component in the water and oil repellent, contains polymerized units of a polymerizable monomer containing active hydrogen atoms, since the active hydrogen atoms are present at positions close to the polymer main chain, the R
f
group receives steric hindrance and can not adequately be involved in the cross-linking reaction. They considered that accordingly, the nature of the coating layer formed from the water and oil repellent tends to be inadequate, and the durability of the water and oil repellency tends to be inadequate.
Therefore, a polymer has been considered in which a group having a reactivity with a cross-linking agent is located at a position sufficiently apart from the polymer main chain so that the R
f
group receives no steric hindrance, in order to let the cross-linking reaction proceed effectively. Further, it has been found that washing durability can be made high without impairing the hand by selecting a hydroxyl group as the group having the reactivity with a cross-linking agent. Further, it has been found also that the object treated by means of the water and oil repellent composition containing such a polymer, has no such a difficulty as coloration.
DISCLOSURE OF THE INVENTION
The present invention provides a water and oil repellent composition comprising a polymer (A) which essentially contains the following polymerized units (A
1
) and the following polymerized units (A
2
), the following surfactant (B), the following aqueous medium (C) and a cross-linkable compound (D):
Polymerized units (A
1
): polymerized units of a (meth)acrylate (a
1
) having a R
f
group;
Polymerized units (A
2
) polymerized units of a polymerizable monomer (a
2
) which essentially contains a polymerizable unsaturated group and a hydroxyl group and in which the polymerizable unsaturated group and the hydroxyl group are connected to each other through 7 or more covalent bonds;
Surfactant (B): a surfactant containing a nonionic surfactant in an amount of from 60 to 100 wt %; and
Aqueous medium (C): water only, or a medium comprising water and a water-soluble organic solvent.
Further, the present invention provides a process for producing a water and oil repellent composition, which comprises emulsifying under pressure and then polymerizing a feed material composition comprising a (meth)acrylate (a
1
) having a R
f
group, a polymerizable monomer (a
2
) which essentially contains a polymerizable unsaturated group and a hydroxyl group and in which the polymerizable unsaturated group and the hydroxyl group are connected to each other through 7 or more covalent bonds, the surfactant (B) and the aqueous medium (C), to obtain an aqueous dispersion having the polymer (A) dispersed in the aqueous medium (C), and then incorporating a cross-linkable compound (D) to the aqueous dispersion.
BEST MODE FOR CARRYING OUT THE INVENTION
In this specification, an acrylate and a methacrylate will generally be referred to as a (meth)acrylate. The same applies to the representation of a (meth)acrylamide or the like. Further, in this specification, a polyfluoroalkyl group is represented by a R
f
group.
A R
f
group is a group having two or more hydrogen atoms in an alkyl group substituted by fluorine atoms. The carbon number of the R
f
group is preferably from 2 to 20, particularly preferably from 6 to 16. The R
f
group may be of a linear structure or a branched structure, and the linear structure is particularly preferred. In the case of a branched structure, it is preferred that the branched portion is located at a terminal portion of the R
f
group and has a short chain of from about 1 to 4 carbon atoms.
The R
f
group may contain halogen atoms other than fluorine atoms. As such other halogen atoms, chlorine atoms are preferred. Further, between a carbon-carbon bond in the R
f
group, an etheric oxygen atom or a thioetheric sulfur atom may be inserted. The structure of the terminal portion of the R
f
group may, for example, be —CF
2
CF
3
, —CF(CF
3
)
2
, —CF
2
H, —CFH
2
or —CF
2
Cl, and —CF
2
CF
3
is preferred.
The number of fluorine atoms in the R
f
group is preferably at least 60%, particularly preferably at least 80%, when represented by [(the number of fluorine atoms in the R
f
group)/(the number of hydrogen atoms contained in an alkyl group corresponding to the same carbon number as the R
f
group)]×100 (%).
Further, the R
f
group is preferably a group having all of hydrogen atoms in an alkyl group substituted by fluorine atoms (i.e. a perfluoroalkyl group) or a group having a perfluoroalkyl group at a terminal portion.
The carbon number of the perfluoroalkyl group is preferably from 2 to 20, particularly preferably from 6 to 16. If the carbon number of the perfluoro group is small, the wa
Kaida Yuriko
Maekawa Takashige
Oharu Kazuya
Shimada Toyomichi
Asahi Glass Company Limited
Lipman Bernard
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
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