Modified-ionomers having improved properties and processability
AssigneeE. I. Du Pont de Nemours and Company
InventorsJohn Chu Chen, John Francis Hagman
Life of this patent
Estimating the term…
Abstract
Ionomers based on ethylene/unsaturated carboxylic acid copolymers are modified with from 0.5 to 15 weight percent adipic acid. The modified-ionomers have improved melt flow and melt processing behavior over unmodified ionomers having a comparable level of neutralization of acid groups present. Certain mechanical properties are improved, particularly stiffness, abrasion resistance and low temperature izod impact. The ionomers modified with adipic acid are in particular suitable for balata ball replacement when formulated as golf ball cover compositions and covers.
Claims14
A composition, which is an adipic acid-modified-ionomer, which comprises;
- (A) an acid-copolymer, or an ionomer which is prepared by neutralizing an acid-copolymer precursor, the acid-copolymer or acid-copolymer precursor comprising a polymer of;
- (a) ethylene,
- (b) 4 to 25 weight percent of at least one dicarboxylic acid selected form the group consisting of itaconic acid, maleic acid, fumaric acid, derivatives thereof, or mixtures of any of these dicarboxylic acids with (meth)acrylic acid and/or acrylic acid;
- (c) 0 to 40 weight percent of a C1-C8-alkyl alkyl acrylate or a C3-C12 alpha olefin,
- the total comonomer content (b) plus (c) not exceeding 50 weight percent, the ionomer being formed by neutralization of from 10 to 90 percent of the total number of carboxylic acid units in the acid-copolymer precursor with sodium, lithium, zinc, magnesium, calcium, or mix of any of these metal ions, and
- (B) an amount of an adipic acid moiety which is adipic acid or the sodium, lithium, zinc, magnesium, calcium, or mix of these metal, salt of adipic acid, such that adipic acid moiety is present at a level of from 0.5 to 15 weight percent calculated as free adipic acid in the adipic acid-modified ionomer, provided the level of neutralization of the final adipic acid-modified-ionomer, calculated as the percent of total acid groups from the acid-copolymer or acid-copolymer precursor (A) and from the adipic acid moiety (B) which are neutralized, is also between 10 and 90 percent.
A process to prepare an adipic acid-modified-ionomer comprising blending in the melt in an extruder,
- a) acid-copolymer precursor,
- b) adipic acid, and
- c) a metal ion source of sodium, lithium, zinc, magnesium and calcium, or mix of any of these, which is an oxide, hydroxide, acetate or mix of these, in one pass through the extruder.
A golf ball having a core and a cover wherein the cover comprises an acid-modified-ionomer, which comprises;
- (A) an acid-copolymer, or an ionomer which is prepared by neutralizing an acid-copolymer precursor, the acid-copolymer or acid-copolymer precursor comprising a polymer of:
- (a) ethylene;
- (b) 4 to 25 weight percent of (meth)acrylic acid, acrylic acid, itaconic acid, maleic acid or fumaric acid or derivatives thereof;
- (c) 0 to 40 weight percent of a C1-C8-alkyl alkyl acrylate or a C3-C12 alpha-olefin;
- the total comonomer content (b) plus (c) not exceeding 50 weight percent or a mixture of ionomers having (a)+(b) and (a)+(b)+(c), the ionomer being formed by neutralization of from 10 to 90 percent of the total number of carboxylic acid units in the acid-copolymer precursor with sodium, lithium, zinc, magnesium, calcium, or mix of any of these metal ions, and
- (B) an amount of an acid moiety selected from the formula
- (i) HOOC--(CH.sub.2)n--COOH where n is 1-12;
- or
- (ii) (HOOC)(OH)C(CH.sub.2 COOH).sub.2 ;
- or
- (iii) HOOC--C.sub.6 H.sub.6 --COOH,
- or the sodium, lithium, zinc, magnesium, calcium, or mix of these metal salts of said acid, such that the acid moiety (i), (ii) or (iii) is present at a level of from 0.5 to 15 weight percent calculated as free acid in the acid-modified ionomer, provided the level of neutralization of the final acid-modified-ionomer, calculated as the percent of total acid groups from the acid-copolymer or acid-copolymer precursor (A) and from the acid moiety (B) which are neutralized, is also between 10 and 90 percent.
Dependencies are inferred from the claim text.