High vinylidene chloride content interpolymer coating resins and method of preparation

Claim 2

A process for preparing, in aqueous emulsion, controlled interpolymer compositions having polymerized therein (a) from about 86 to about 92 mole percent vinylidene chloride; (b) from about 14 to about 8 mole percent of a mixture of methyl methacrylate and a comonomer selected from the group consisting of acrylonitrile, methacrylic acid, and methacrylonitrile, said mixture of methyl methacrylate and the comonomer having a molar ratio of the comonomer to methyl methacrylate of from about 0.2:1 to 5:1; and (c) from about 0.5 to about 1.0 weight percent itaconic acid based on weight of (a) plus (b); said interpolymer compositions having a relative viscosity of from about 1.3 to about 1.7 at 25° C. as a 1 percent solution in tetrahydrofuran; said interpolymer compositions being capable of forming generally haze-free solutions when present in an amount of about 20 percent solids in a solvent mixture, said solvent mixture comprising about 65 weight percent tetrahydrofuran based on solvent mixture weight, and about 35 weight percent toluene based on solvent mixture weight, said process comprising the sequential steps of: (A) initiating emulsion polymerization by forming a seed latex, the seed latex being formed in a batch emulsion polymerization process which comprises: (1) adding a first monomer charge to an aqueous emulsion polymerization medium, the first monomer charge comprising from about 3 to about 8 weight percent of a principal mixture of monomers, the principal mixture of monomers comprising from about 86 to about 92 mole percent vinylidene chloride and from about 14 to about 8 mole percent of a comonomer mixture of methyl methacrylate and a comonomer selected from the group consisting of acrylonitrile, methacrylic acid, and methacrylonitrile, said comonomer mixture having a molar ratio of the comonomer to methyl methacrylate of from about 0.2:1 to about 5:1, the polymerization medium comprising water, an emulsifier and from about 0.5 to about 1.0 weight percent itaconic acid based on the principal mixture of monomers; (2) adding a polymerization initiator to said emulsion polymerization medium, the initiator being added at a generally constant rate; (3) continuing seed latex formation under autogenous pressure until a pressure drop in vapor pressure of monomers in the polymerization medium of from about 1.8 to about 2.2 pounds per square inch occurs; (B) continuing polymerization under autogenous pressure by adding to the emulsion polymerization medium: (1) a second monomer charge in an amount between about 85 and 92 weight percent of the principal mixture of monomers as in (A)(1), said second monomer charge being added at a generally constant rate, the rate being sufficient to continually provide an excess of unreacted monomers in the polymerization medium, said excess being generally from about 2 to about 10 weight percent based on weight of the polymerization medium; and (2) the polymerization initiator at generally the same constant rate of addition as in (A)(2); and (C) generally immediately following addition of all of the second monomer charge, finishing polymerization in a predetermined time interval T, the time interval T having at least a first portion and a second portion, by: (1) continuing to add the polymerization initiator at generally the same constant rate of addition as in (A)(2) and (B)(2), the initiator being added throughout the time interval T; and (2) adding a third monomer charge in an amount between about 2 and 12 weight percent of the principal mixture of monomers as in (A)(1), said third monomer charge being added over the first portion of the time interval T in such a manner that the vapor pressure of monomers in the emulsion polymerization medium is reduced smoothly as reflected by a time-pressure curve wherein time is plotted on the abscissa and pressure is plotted on the ordinate, the time-pressure curve being generally free of discontinuities from the beginning of the time interval T to the end thereof and having a shape, the shape being that of a line which is generally concave downward.

Claim 3

The process of claim 1, wherein said interpolymer has a minimum heat-seal temperature of from about 70° C. to about 140° C. when deposited as a coating with a coating weight of about 4 grams per square meter.

Claim 4

The process of claim 1, wherein said interpolymer has a minimum heat seal temperature of from about 95° C. to about 130° C. when deposited as a coating with a coating weight of about 4 grams per square meter.

Claim 5

The process of claim 1, wherein the interpolymer, when deposited as a coating from a tetrahydrofuran lacquer solution at a coating weight of 4 grams per square meter, has a water vapor transmission rate of no greater than about 0.25 grams of water/100 square inches/24 hours at 38° C., an oxygen transmission rate of no greater than about 0.30 cubic centimeters of oxygen/100 square inches/24 hours/one atmosphere of oxygen at 25° C. and a crystallization ratio at 15 minutes at 80° C. of from about 0.5 to about 2.

Claim 6

The process of claim 1, wherein the generally haze-free solution has a haze value of at least 80 percent transmission of visible light at 640 nanometers.

Claim 7

The process of claim 1, wherein the generally haze-free solution has a haze value of at least 85 percent transmission of visible light at 640 nanometers.

Claim 8

The process of claim 1, wherein the mixture of monomers comprises about 90 mole percent vinylidene chloride and about 10 mole percent of the mixture of methacrylic acid and methyl methacrylate.

Claim 9

A process for preparing, in aqueous emulsion, controlled interpolymer compositions comprising (a) from about 86 to about 92 mole percent vinylidene chloride; (b) from about 14 to about 8 mole percent of a mixture of methyl methacrylate and a comonomer selected from the group consisting of acrylonitrile, methacrylic acid and methacrylonitrile, said mixture of methyl methacrylate and the comonomer having a molar ratio of the comonomer to methyl methacrylate of from about 0.2:1 to 5:1; and (c) from about 0.5 to about 1.0 weight percent itaconic acid based on weight of (a) plus (b); said interpolymer compositions having a relative viscosity of from about 1.3 to about 1.7 at 25° C. as a 1 percent solution in tetrahydrofuran; said interpolymer compositions having a haze value of at least 80 percent transmission of visible light at 640 nanometers when present in an amount of about 20 percent solids in a solvent mixture, said solvent mixture comprising about 65 weight percent tetrahydrofuran based on solvent mixture weight, and about 35 weight percent toluene based on solvent mixture weight; said interpolymer compositions, when deposited as a coating from a tetrahydrofuran lacquer solution at a coating weight of 4 grams per square meter, having a water vapor transmission rate of no greater than about 0.25 grams of water/100 square inches/24 hours at 38° C., an oxygen transmission rate of no greater than about 0.30 cubic centimeters/100 square inches/24 hours/one atmosphere of oxygen at 25° C., a minimum heat seal temperature of from about 95° C. to about 125° C. and a crystallization ratio at 15 minutes at 80° C. of from about 0.5 to about 2, said process comprising the sequential steps of: (A) initiating emulsion polymerization by forming a seed latex, the seed latex being formed in a batch emulsion polymerization process which comprises: (1) adding a first monomer charge to an aqueous emulsion polymerization medium, the first monomer charge comprising from about 3 to about 8 weight percent of a principal mixture of monomers, the principal mixture of monomers comprising from about 86 to about 92 mole percent vinylidene chloride and from about 14 to about 8 mole percent of a comonomer mixture of methyl methacrylate and a comonomer selected from the group consisting of acrylonitrile, methacrylic acid and methacrylonitrile, said comonomer mixture having a molar ratio of the comonomer to methyl methacrylate of from about 0.2:1 to about 5:1, the polymerization medium comprising water, an emulsifier and from about 0.5 to about 1.0 weight percent itaconic acid based on the principal mixture of monomers; (2) adding a polymerization initiator to said emulsion polymerization medium, the initiator being added at a generally constant rate; (3) continuing seed latex formation under autogenous pressure until a pressure drop in vapor pressure of monomers in the emulsion polymerization medium of from about 1.8 to about 2.2 pounds per square inch occurs; (B) continuing polymerization under autogenous pressure by adding to the emulsion polymerization medium: (1) a second monomer charge in an amount between about 85 and 92 weight percent of the principal mixture of monomers as in (A)(1), said second monomer charge being added at a generally constant rate sufficient to continually provide an excess of unreacted monomers in the polymerization medium, said excess being generally from about 2 to about 10 weight percent based on weight of the polymerization medium; and (2) the polymerization initiator at generally the same constant rate of addition as in (A)(2); and (C) generally immediately following addition of all of the second monomer charge, finishing polymerization in a predetermined time interval T, the time interval T having a first fractional part, a second fractional part and a third fractional part, by: (1) continuing to add the polymerization initiator at generally the same constant rate of addition as in (A)(2) and (B)(2), the initiator being added throughout the time interval T; and (2) adding a third monomer charge in an amount between about 2 and 12 weight percent of the principal mixture of monomers as in (A)(1) said third monomer charge being added over the time interval T at the following sequential rates: (a) about one-half the rate of addition of the second monomer charge as in (B)(1) for the first fractional part of the time interval T, the first fractional part being about T/6; (b) about one-fourth the rate of addition of the second monomer charge as in (B)(1) for the second fractional part of the time interval T, the second fractional part being about T/3; and (c) adding only the initiator during the third fractional part, the third fractional part being about T/2.

Claim 10

A process for preparing, in aqueous emulsion, controlled interpolymer compositions comprising (a) from about 86 to about 92 mole percent vinylidene chloride; (b) from about 14 to about 8 mole percent of a mixture of methyl methacrylate and a comonomer selected from the group consisting of acrylonitrile, methacrylic acid and methacrylonitrile, said mixture of methyl methacrylate and the comonomer having a molar ratio of the comonomer to methyl methacrylate of from about 0.2:1 to 5:1; and (c) from about 0.5 to about 1.0 weight percent itaconic acid based on weight of (a) plus (b); said interpolymer compositions having a relative viscosity of from about 1.3 to about 1.7 at 25° C. as a 1 percent solution in tetrahydrofuran; said interpolymer compositions having a haze value of at least 80 percent transmission of visible light at 640 nanometers when present in an amount of about 20 percent solids in a solvent mixture, said solvent mixture comprising about 65 weight percent tetrahydrofuran based on solvent mixture weight, and about 35 weight percent toluene based on solvent mixture weight; said interpolymer compositions, when deposited as a coating from a tetrahydrofuran lacquer solution at a coating weight of 4 grams per square meter, having a water vapor transmission rate of no greater than about 0.25 grams of water/100 square inches/24 hours at 38° C., an oxygen transmission rate of no greater than about 0.30 cubic centimeters/100 square inches/24 hours/one atmosphere of oxygen at 25° C., a minimum heat seal temperature of from about 95° C. to about 125° C. and a crystallization ratio at 15 minutes at 80° C. of from about 0.5 to about 2, said process comprising the sequential steps of: (A) initiating emulsion polymerization by forming a seed latex, the seed latex being formed in a batch emulsion polymerization process which comprises: (1) adding a first monomer charge to an aqueous emulsion polymerization medium, the first monomer charge comprising from about 3 to about 8 weight percent of a principal mixture of monomers, the principal mixture of monomers comprising from about 86 to about 92 mole percent vinylidene chloride and from about 14 to about 8 mole percent of a comonomer mixture of methyl methacrylate and a comonomer selected from the group consisting of acrylonitrile, methacrylic acid and methacrylonitrile, said comonomer mixture having a molar ratio of the comonomer to methyl methacrylate of from about 0.2:1 to about 5:1, the polymerization medium comprising water, an emulsifier and from about 0.5 to about 1.0 weight percent itaconic acid based on the principal mixture of monomers; (2) adding a polymerization initiator to said emulsion polymerization medium, the initiator being added at a generally constant rate; (3) continuing seed latex formation under autogenous pressure until a pressure drop in vapor pressure of monomers in the emulsion polymerization medium of from about 1.8 to about 2.2 pounds per square inch occurs; (B) continuing polymerization under autogenous pressure by adding to the emulsion polymerization medium: (1) a second monomer charge in an amount between about 85 and 92 weight percent of the principal mixture of monomers as in (A)(1), said second monomer charge being added at a generally constant rate sufficient to continually provide an excess of unreacted monomers in the polymerization medium, said excess being generally from about 2 to about 10 weight percent based on weight of the polymerization medium; and (2) the polymerization initiator at generally the same constant rate of addition as in (A)(2); and (C) generally immediately following addition of all of the second monomer charge, finishing polymerization in a predetermined time interval T, the time interval T having a first fractional part, a second fractional part and a third fractional part, by: (1) continuing to add the polymerization initiator at generally the same constant rate of addition as in (A)(2) and (B)(2), the initiator being added throughout the time interval T; and (2) adding a third monomer charge in an amount between about 2 and 12 weight percent of the principal mixture of monomers as in (A)(1) said third monomer charge being added over the time interval T at the following sequential rates: (a) about one-half the rate of addition of the second monomer charge as in (B)(1) for the first fractional part of the time interval T, the first fractional part being about T/6; (b) about one-fourth the rate of addition of the second monomer charge as in (B)(1) for the second fractional part of the time interval T, the second fractional part being about T/3; and (c) adding only the initiator during the third fractional part, the third fractional part being about T/2.

Claim 11

The interpolymer produced in accordance with the process of claim 1 or claim 8.

Claim 12

A crystalline, controlled composition interploymer having polymerized therein (a) from about 86 to about 92 mole percent vinylidene chloride; (b) from about 14 to about 8 mole percent of a mixture of methyl methacrylate and a comonomer selected from the group consisting of acrylonitrile, methacrylic acid and methacrylonitrile, said mixture of methyl methacrylate and the comonomer having a molar ratio of the comonomer to methyl methacrylate of from about 0.2:1 to 5:1; and (c) from about 0.5 to about 1.0 weight percent itaconic acid based on weight of (a) plus (b); said interpolymer having a relative viscosity of from about 1.3 to about 1.7 at 25° C. as a 1 percent solution in tetrahydrofuran; said interpolymer being capable of forming a solution having a haze value of at least 80 percent transmission of visible light at 640 nanometers when present in an amount of about 20 percent solids in a solvent mixture, said solvent mixture comprising about 65 weight percent tetrahydrofuran based on solvent mixture weight, and about 35 weight percent toluene based on solvent mixture weight.

Claim 13

A crystalline, controlled composition interploymer having polymerized therein (a) from about 86 to about 92 mole percent vinylidene chloride; (b) from about 14 to about 8 mole percent of a mixture of methyl methacrylate and a comonomer selected from the group consisting of acrylonitrile, methacrylic acid and methacrylonitrile, said mixture of methyl methacrylate and the comonomer having a molar ratio of the comonomer to methyl methacrylate of from about 0.2:1 to 5:1; and (c) from about 0.5 to about 1.0 weight percent itaconic acid based on weight of (a) plus (b); said interpolymer having a relative viscosity of from about 1.3 to about 1.7 at 25° C. as a 1 percent solution in tetrahydrofuran; said interpolymer being capable of forming a solution having a haze value of at least 80 percent transmission of visible light at 640 nanometers when present in an amount of about 20 percent solids in a solvent mixture, said solvent mixture comprising about 65 weight percent tetrahydrofuran based on solvent mixture weight, and about 35 weight percent toluene based on solvent mixture weight.

Claim 14

The interploymer of claim 10 further having a minimum heat-seal temperature of from about 70° C. to about 140° C., a water vapor transmission rate of no greater than 0.25 grams of water/100 square inches/24 hours at 38° C., an oxygen transmission rate of no greater than about 0.30 cubic centimeter of oxygen/100 square inches/24 hours/one atmosphere of oxygen at 25° C. and a crystallization ratio at 15 minutes at 80° C. of from about 0.5 to about 2 when deposited as a coating from a tetrahydrofuran laquer solution at a coating weight of 4 grams/square meter.

Claim 15

The interpolymer of claim 10 further having a minimum heat-seal temperature of from about 95° C. to about 130° C. when deposited as a coating with a coating weight of about 4 grams per square meter.

Claim 16

The interpolymer of claim 10 further having a haze value of at least 85 percent transmission of visible light at 640 nanometers.

Claim 17

A crystalline, controlled composition interpolymer having polymerized therein (a) from about 86 to about 92 mole percent vinylidene chloride; (b) from about 14 to about 8 mole percent of a mixture of methyl methacrylate and a comonomer selected from the group consisting of acrylonitrile, methacrylic acid and methacrylonitrile, said mixture of methyl methacrylate and the comonomer having a molar ratio of the comonomer to methyl methacrylate of from about 0.2:1 to 5:1; and (c) from about 0.5 to about 1.0 weight percent itaconic acid based on weight of (a) plus (b); said interpolymer having a relative viscosity of from about 1.3 to about 1.7 at 25° C. as a 1 percent solution in tetrahydrofuran; said interpolymer having a haze value of at least 80 percent transmission of visible light at 640 nanometers when present in an amount of about 20 percent solids in a solvent mixture, said solvent mixture comprising about 65 weight percent tetrahydrofuran based on solvent mixture weight, and about 35 weight percent toluene based on solvent mixture weight; the interpolymer having a minimum heat-seal temperature of from about 70° C. to about 140° C., a water vapor transmission rate of no greater than 0.25 grams of water/100 square inches/24 hours at 38° C., an oxygen transmission rate of no greater than about 0.30 cubic centimeter of oxygen/100 square inches/24 hours/one atmosphere of oxygen at 25° C., and a crystallization ratio at 15 minutes at 80° C. of from about 0.5 to about 2 when deposited as a coating from a tetrahydrofuran lacquer solution at a coating weight of 4 grams/square meter.

Claim 18

A crystalline, controlled composition interpolymer having polymerized therein (a) from about 86 to about 92 mole percent vinylidene chloride; (b) from about 14 to about 8 mole percent of a mixture of methyl methacrylate and a comonomer selected from the group consisting of acrylonitrile, methacrylic acid and methacrylonitrile, said mixture of methyl methacrylate and the comonomer having a molar ratio of the comonomer to methyl methacrylate of from about 0.2:1 to 5:1; and (c) from about 0.5 to about 1.0 weight percent itaconic acid based on weight of (a) plus (b); said interpolymer having a relative viscosity of from about 1.3 to about 1.7 at 25° C. as a 1 percent solution in tetrahydrofuran; said interpolymer having a haze value of at least 80 percent transmission of visible light at 640 nanometers when present in an amount of about 20 percent solids in a solvent mixture, said solvent mixture comprising about 65 weight percent tetrahydrofuran based on solvent mixture weight, and about 35 weight percent toluene based on solvent mixture weight; the interpolymer having a minimum heat-seal temperature of from about 70° C. to about 140° C., a water vapor transmission rate of no greater than 0.25 grams of water/100 square inches/24 hours at 38° C., an oxygen transmission rate of no greater than about 0.30 cubic centimeter of oxygen/100 square inches/24 hours/one atmosphere of oxygen at 25° C., and a crystallization ratio at 15 minutes at 80° C. of from about 0.5 to about 2 when deposited as a coating from a tetrahydrofuran lacquer solution at a coating weight of 4 grams/square meter.