Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
2001-10-23
2003-10-07
Dawson, Robert (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C106S031130, C106S287100, C106S287150, C526S279000, C526S319000, C526S320000, C528S025000, C528S026000, C528S032000, C528S033000
Reexamination Certificate
active
06630522
ABSTRACT:
DETAILED DESCRIPTION OF THE INVENTION
1. Technical Field to Which the Invention Belongs
This invention relates to flow-and-leveling agents for paints and inks, which, when added to paints and inks in minor amounts, can impart to the paints and inks flow-and-leveling property in the occasions of their application or printing and at the same time can prevent occurrence of coating or printing defects even in the presence of foreign matters which are a cause of ruptures in coating or printing step.
2. Prior Art
Paints which are applied by industrial line operation, such as those high quality paints for automotives, precoat metal (PCM) paints and paints for household appliances, are required to exhibit not only anti-corrosion property but also high quality finish excelling in appearance. It is, therefore, essential that the finished surfaces are free from cissing, cratering, fish-eyes, clouds and the like and are level and smooth. As paint additives for imparting such functions, surface control agents such as flow-and-leveling agents, defoamers, anti-popping agents, brighteners and anti-rupture agents are used.
Conventionally, atomizing coating such as air spray or high-speed continuous coating using roll coater or the like have been practiced in line coating. According to these coating methods, mist of the lubricants used on compressors, roll coater machines and the like or mist of the used paints may deposit on the surfaces of the objects being painted and cause occurrence of ruptures. Besides this problem, in coating lines wherein coating and sanding are repeated plural times as in the case of coating automobile bodies, ruptures caused by dust formed during sanding with sand paper or soiling with operators'hands can create a problem. (These matters which can cause ruptures are hereafter collectively referred to as “foreign dust”).
As a means to solve this problem of ruptures at the coating time, heretofore modified silicone oils or vinyl ether polymers have been used as additives. For example, Japanese Patent Publication Hei 1 (1989)-234478B1 taught the usefulness of vinyl ether polymers having C
2
-C
4
alkyl groups as anti-rupture agent.
THE PROBLEM TO BE SOLVED BY THE INVENTION
Recently high-solid paints for environmental preservation or paints free of melamine resin curing agents to cope with acid precipitation are commercialized. When modified silicone oils or vinyl ether polymers are added to those recently marketed paints, however, they tend to adversely affect re-coating property of those paints (i.e., interlayer-adherability of over-painted layers is impaired or color tone of top coating is changed).
Accordingly, therefore, the object of the present invention is to provide flow-and-leveling agents which prevent ruptures caused by foreign dust and give smooth and level painted surfaces, without interfering with the paints' recoating property.
MEANS FOR SOLVING THE PROBLEM
As a result of various studies, we have come to discover that the above object of the invention is accomplished by blending a flow-and-leveling agent comprising a copolymer having a number-average molecular weight of 1,000-60,000, preferably 2,000-30,000 with paints, said copolymer being formed by copolymerizing
2-50% by weight, preferably 5-35% by weight of silicone oil containing an acryloyloxy group or methacryloyloxy group, as monomer (A) which is expressed by the following general formula (I):
in which R
1
stands for hydrogen or methyl,
R
2
stands for C
1
-C
10
alkylene,
R
3
stands for C
1
-C
4
alkyl, and
n stands for an integer of 5-100,
with
50-98% by weight, preferably 65-95% by weight, of an acrylic acid ester or methacrylic acid ester as monomer(B) of the following general formula (II):
in which R
4
stands for hydrogen or methyl, and
R
5
stands for C
1
-C
12
alkyl
and/or an acrylic acid ester or methacrylic acid ester as monomer (C) of the following general formula (II)
in which R
6
stands for hydrogen or methyl,
R
7
stands for hydrogen or C
1
-C
18
alkyl,
n stands for an integer of 2-4, and
m stands for an integer of 1-50.
We have also discovered that the object of the present invention could equally be accomplished by blending a flow-and-leveling agent with paints, said agent comprising a copolymer having a number-average molecular weight of 1,000-60,000, preferably 2,000-30,000, which is formed by copolymerizing with said monomer (A) and monomer (B) and/or monomer (C), still another monomer (D), which has a polymerizable double bond and is copolymerizable with said monomers, of an amount not exceeding 50% by weight based on the total weight of said monomers (A) and (B) and/or (C).
Where the amount of monomer (A) is less than 2% by weight, sufficient anti-rupture effect cannot be recognized. Whereas, when it exceeds 50% by weight, re-coating property of the paint is adversely affected.
Those specific (meth)acrylic acid esters [monomer (B) and/or monomer (C)] are used as the copolymerizing components in an amount of 50-98% by weight, for securing favorable flow-and-leveling property. Use of monomers other than those cannot impart sufficient flow-and-leveling property to the paints. When the degree of polymerization (m) of the polyalkylene glycol as monomer (C) exceeds 50, not only satisfactory flow-and-leveling property cannot be expected, but also physical properties of painted films are liable to be adversely affected. Where monomers (B) and (C) are concurrently used, their quantitative ratio is optional, so long as their sum falls within the range of 50-98% by weight of the copolymer.
Those copolymers formed of monomer (A) and monomer (B) and/or monomer (C) and monomer (D) can impart good flow-and-leveling property and anti-rupture property, similarly to said two- or three-component copolymers, so long as the use ratio of the monomer (D) is within the specified ratio.
Where the number-average molecular weight of the copolymer is less than 1,000 or more than 60,000, sufficient flow-and-leveling property cannot be obtained by blending it with paints, because its orientability on the painted surfaces at the coating time is insufficient.
Examples of said silicone oil (monomer A) represented by the general formula (I), which has an acryloyloxy group or a methacryloyloxy group include reactive silicones having methacryloyloxy groups (Silaplane™ FM-0711, FM-0721 and FM-0725, Chisso Corporation; AK-5 and AK-30, Toagosei Co., Ltd.).
Examples of (meth)acrylic acid esters (monomer B) represented by the general formula (II) include: methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, i-propyl (meth)acrylate, n-butyl (meth)acrylate, i-butyl (meth)acrylate, tert-butyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isononyl (meth)acrylate and lauryl (meth)acrylate.
Examples of said (meth)acrylic acid esters (monomer C) represented by the general formula (III) include: 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-butoxyethyl (meth)acrylate, 2-octoxyethyl (meth)acrylate, 2-lauroxyethyl (meth)acrylate, 3-methoxybutyl (meth)acrylate, 4-methoxybutyl (meth)acrylate, ethylcarbitol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate (in which the degree of polymerization of ethylene glycol is 2-50), methoxypolypropylene glycol (meth)acrylate (in which the degree of polymerization of propylene glycol is 2-50), methoxy-poly (ethylene-propylene) glycol (meth)acrylate (in which the degree of polymerization of ethylene glycol-propylene glycol is 2-50), methoxy-poly (ethylene-tetramethylene) glycol (meth)acrylate (in which the degree of polymerization of ethylene glycol-tetramethylene glycol is 2-50), butoxy-poly (ethylene-propylene) glycol (meth)acrylate (in which the degree of polymerization of ethylene glycol-propylene glycol is 2-50), octoxy-poly (ethylene-propylene) glycol (meth)acrylate (in which the degree of polymerization of ethylene glycol-propylene glycol is 2-50), and lauroxy-polyethylene glycol (meth)acrylate (in which the degree of polymerization of ethylene glycol is 2-50).
A copolymer according to t
Kawahito Shigehiro
Kawase Masafumi
Dawson Robert
Kusumoto Chemicals Ltd.
Robertson Jeffrey B.
Sherman & Shalloway
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