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US 2003/0147946 A1Published application
Aqueous dispersions of crystalline polymers and uses
AssigneeLandec Corporation
InventorsRay F. Stewart, Natarajan Balachander, Steven P. Bitler, Loc Phan, Valentine Y. Yoon
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Abstract
Aqueous dispersions of crystalline polymers based on hydrophobic monomers, preferably on a mixture of hydrophobic and hydrophilic monomers which contains a crosslinking monomer, particularly side chain crystalline (SCC) polymers. The dispersions are useful for providing coatings on substrates, particularly on seeds (whose dormancy is thus extended) and on fibrous substrates, particularly human hair (which thus becomes heat-settable).
Claims15
A substrate having a solid polymeric coating thereon, the coating having been obtained by
- (1) applying to the substrate an aqueous dispersion of solid particles comprising a crystalline polymer, the polymer (a) having a melting point Tm and (b) comprising units derived from a hydrophobic monomer, and
- (2) evaporating water from the dispersion to form the solid polymeric coating;
- the coating having at least one of the following characteristics:
- (A) at temperatures below Tm, the coating is substantially impermeable to water (as hereinbefore defined), and at temperatures above Tm, the coating is substantially permeable to water (as hereinbefore defined);
- (B) the polymer is a crosslinked polymer having a gel content of at least 50%,
- (C) the polymer is derived from a monomer component comprising:
- (i) a hydrophobic monomer component comprising a first hydrophobic monomer, the first hydrophobic monomer being such that a homopolymer thereof is crystalline and has a melting point Tc, and
- (ii) a hydrophilic monomer component comprising a hydrophilic monomer, the ratio by weight of the hydrophobic monomer component to the hydrophilic monomer component being 10:1 to 50:1;
- (D) the polymer is derived from a monomer component comprising a hydrophobic monomer component comprising (i) a first hydrophobic monomer, the first hydrophobic monomer being such that a homopolymer thereof is crystalline and has a melting point Tc, and (ii) a second hydrophobic monomer which
- (a) is such that a homopolymer thereof is amorphous and has a glass transition point Tg which is less than Tc, and
- (b) is present in amount such that Tm is (Tc−5)° C. or less;
- (E) the polymer is derived from a monomer component comprising a hydrophobic monomer component comprising (i) a first hydrophobic monomer, the first hydrophobic monomer being such that a homopolymer thereof is crystalline and has a melting point Tc, and (ii) a second hydrophobic monomer which
- (a) is such that a homopolymer thereof is amorphous and has a glass transition point Tg which is more than Tc, and
- (b) is present in amount such that the coating has a tack at (Tc+10)° C. which is less than the tack at (Tc+10)° C. of a coating formed under the same conditions from a composition which is identical except that the crystalline polymer does not contain units derived from the second hydrophobic monomer;
- (F) the polymer is derived from a monomer component comprising:
- (i) a hydrophobic monomer component comprising a hydrophobic monomer, the hydrophobic monomer being such that a homopolymer thereof is crystalline and has a melting point Tc;
- (ii) a hydrophilic monomer component comprising a hydrophilic monomer;
- and
- (iii) a crosslinking monomer having at least two polymerizable groups;
- (G) the polymer is derived from a monomer component comprising one or more monomers containing carboxyl groups, at least 75% of the carboxyl groups having been neutralized;
- (H) the polymer is crosslinked by an external crosslinker (as hereinbefore defined);
- (I) the particles of the dispersion have coalesced to form a continuous coating, but retain a particulate character;
- (J) the coating contains less than 1% of unreacted monomer, based on the weight of the polymer;
- and
- (K) at least some of the particles comprise a core comprising said crystalline polymer and a coating around the core comprising a substantially amorphous polymer.
22 more elements
A method of treating a seed or other organism to extend its dormancy, the method comprising:
- (a) applying to the organism a non-phytotoxic coating composition which comprises:
- (i) water, and
- (ii) suspended in the water, particles which comprise a crystalline polymer having a melting point Tm of 0° to 40° C.;
- and
- (b) causing water to evaporate from the composition after the composition has been applied to the organism, thereby forming a coating which has a particulate character and
- (i) at temperatures below Tm is substantially impermeable to water (as hereinafter defined), and
- (ii) at temperatures above Tm is substantially permeable to water (as hereinafter defined).
4 more elements
A composition which comprises:
- (a) water,
- (b) suspended in the water, particles comprising a crosslinked crystalline polymer which
- (i) has a gel content of at least 50%,
- (ii) contains less than 1% of unreacted monomer, and
- (iii) is derived from a monomer component comprising:
- 1) a hydrophobic monomer component comprising a first hydrophobic monomer, the first hydrophobic monomer being such that a homopolymer thereof is crystalline and has melting point Tc, and
- 2) a hydrophilic monomer component comprising a hydrophilic monomer, and
- 3) a crosslinking monomer having at least two polymerizable groups;
- and
- (c) a surfactant.
7 more elements
A method for preparing an aqueous suspension, the method comprising the steps of:
- (a) providing an aqueous reaction medium comprising:
- (i) water,
- (ii) a first monomer component comprising a hydrophobic monomer component comprising a first hydrophobic monomer, the first hydrophobic monomer being such that a homopolymer thereof is crystalline, and
- (iii) a surfactant;
- b) polymerizing the first monomer component to form a crystalline polymer in the form of particles suspended in the reaction medium;
- and
- c) polymerizing a second monomer component to form a shell on said particles,
- the amounts of said first and second monomer components being such that the product of step (c) has a solids content of at least 30%, and
- the amount of surfactant being such that the product of step (c) contains particles having an average particle size of less than 0.5 microns and a residual monomer content of less than 1%, based on the weight of the first and second monomer components.
6 more elements
A composition suitable for use in setting a flexible fibrous material, the composition comprising:
- (a) water;
- (b) particles suspended in the water, the particles comprising a crystalline polymer;
- and
- c) an effective amount of an additive having a desired effect on the fibrous material.
1 more element
A composition according to claim 21, wherein the crystalline polymer has a Tm of 40 to 60° C., the fibrous material is human hair, and the additive is a hair care additive.
A composition according to claim 21 wherein the fibrous material is a fabric and the additive is a fabric-treating compound.
Dependencies are inferred from the claim text.