阅读说明：本技术 耐蠕变性增强的乙烯酸共聚物的离聚物 (Ionomers of ethylene acid copolymers with enhanced creep resistance ) 是由 R·T·H·周 于 2019-07-26 设计创作，主要内容包括：根据一个实施例,一种离聚物包括乙烯酸共聚物的经中和的共混物。所述乙烯酸共聚物包含以下各者的聚合反应产物：乙烯；按所述乙烯酸共聚物中存在的单体的总重量％计,2至20重量％的单羧酸单体；按所述乙烯酸共聚物中存在的单体的总重量％计,2至15重量％的不饱和二羧酸单体。在离聚物中,所述乙烯酸共聚物的总酸单元的10至60％被镁阳离子中和。(According to one embodiment, an ionomer comprises a neutralized blend of ethylene acid copolymers. The ethylene acid copolymer comprises the polymerization reaction product of: ethylene; 2 to 20 weight percent monocarboxylic acid monomer based on the total weight percent of monomers present in the ethylene acid copolymer; from 2 to 15 weight percent of unsaturated dicarboxylic acid monomer, based on the total weight percent of monomers present in the ethylene acid copolymer. In the ionomer, 10 to 60% of the total acid units of the ethylene acid copolymer are neutralized with magnesium cations.)

1. An ionomer comprising an ethylene acid copolymer, wherein:

the ethylene acid copolymer comprises the polymerization reaction product of:

ethylene;

2 to 20 weight percent monocarboxylic acid monomer based on the total weight percent of monomers present in the ethylene acid copolymer;

2 to 15 weight percent, based on the total weight percent of monomers present in the ethylene acid copolymer, of unsaturated dicarboxylic acid monomers; and

wherein 10 to 70 mole% of the total acid units of the ethylene acid copolymer are neutralized with magnesium cations;

wherein the ionomer exhibits a dimensional change of less than 25% at a temperature of 100 ℃ over a 30 minute period at a stress of 20 psi.

2. An ionomer comprising a first ethylene acid copolymer and a second ethylene acid copolymer, wherein:

the first ethylene acid copolymer is the polymerization reaction product of:

ethylene;

2 to 20 weight percent monocarboxylic acid, based on the total weight percent of monomers present in the first ethylene acid copolymer; and

from 0 to 40 weight percent of an alkyl acrylate, based on the total weight percent of monomers present in the first ethylene acid copolymer;

the second ethylene acid copolymer is a polymerization reaction product of:

the amount of ethylene is such that the amount of ethylene,

from 0 to 20 weight percent monocarboxylic acid, based on the total weight percent of monomers present in the second ethylene-based polymer;

from 0 to 40 weight percent of an alkyl acrylate, based on the total weight percent of monomers present in the second ethylene acid copolymer; and

2 to 15 weight percent of unsaturated dicarboxylic acid monomer, based on the total weight percent of monomers present in the second ethylene acid copolymer; and

wherein the ratio of the first ethylene acid copolymer to the second ethylene acid copolymer is from 90/10 weight percent to 10/90 weight percent;

wherein at least 70 mole% of the total acid units of the blend are neutralized and from 10 to 70 mole% of said total acid units of the blend are neutralized by magnesium cations.

3. The ionomer of any preceding claim, wherein the monocarboxylic acid monomers comprise one or more of acrylic acid, methacrylic acid, or a combination thereof.

4. The ionomer of any preceding claim, wherein the dicarboxylic acid comprises maleic anhydride, monomethyl maleic anhydride, monoethyl maleic anhydride, monopropyl maleic anhydride, monobutyl maleic anhydride, or a combination thereof.

5. The ionomer of any one of claims 2 to 4, wherein the blend is further neutralized with at least one additional metal cation selected from the group consisting of Zn, Li, and Na.

6. The ionomer of any one of claims 2 to 5, wherein the total acid units of the blend are neutralized in the range of 10 to 80 mole%, and wherein 20 to 60 mole% of the total acid units of the blend are neutralized by magnesium cations of magnesium salts.

7. The ionomer of any one of the preceding claims, wherein the alkyl acrylate comprises methyl acrylate, ethyl acrylate, n-butyl acrylate, or isobutyl acrylate, or a combination thereof.

Technical Field

Embodiments of the present disclosure relate generally to ionomer resins, and specifically to ionomers comprising the polymerization reaction product of: ethylene, monocarboxylic acid monomers, unsaturated dicarboxylic acid monomers, alkyl acrylate monomers, and combinations thereof, the ionomer being at least partially neutralized by magnesium cations.

Background

Ionomers are materials commonly used in a variety of applications because they have higher tensile strength, greater transparency, better abrasion resistance, and higher stiffness than the precursor acid copolymers. For example, ionomers of ethylene acid copolymers have found use in many applications, such as food packaging, foam parts, injection molded parts (e.g., cosmetic containers), and golf ball components.

Although ionomers are useful in many applications, ionomers have limited service temperatures, which limits their use in applications requiring creep resistance at temperatures above 60 ℃. For example, ionomers can deform under stress at temperatures above 60 ℃. Dynamic mechanical thermal analysis indicated a substantial decrease in mechanical strength of the ionomer at about 60 ℃, which was associated with the onset of dissociation of the ionic aggregates.

Disclosure of Invention

Accordingly, it may be beneficial to develop alternative ionomers having improved creep resistance while maintaining the physical and chemical properties of the ionomer, such as optical clarity and toughness.

In one or more embodiments, the ionomers of the present disclosure include ethylene acid copolymers, wherein the ethylene acid copolymers comprise the polymerization reaction product of: ethylene; 2 to 20 weight percent monocarboxylic acid monomer based on the total weight percent of monomers present in the ethylene acid copolymer; and 2 to 15 weight percent of unsaturated dicarboxylic acid monomer, based on the total weight percent of monomers present in the ethylene acid copolymer. The ionomer comprises 10 to 70 mole% of the total acid units of the ethylene acid copolymer neutralized with magnesium cations. The ionomer exhibits a dimensional change of less than 25% at a temperature of 100 ℃ over a 30 minute period under a stress of 20 psi.

In one or more embodiments, the ionomer comprises a first ethylene acid copolymer and a second ethylene acid copolymer. The first ethylene acid copolymer is the polymerization reaction product of: ethylene; 2 to 20 weight percent monocarboxylic acid, based on the total weight percent of monomers present in the first ethylene acid copolymer; and 0 to 40 weight percent of an alkyl acrylate, based on the total weight percent of monomers present in the first ethylene acid copolymer. The second ethylene acid copolymer of the ionomer is the polymerization reaction product of: ethylene; from 0 to 20 weight percent monocarboxylic acid, based on the total weight percent of monomers present in the second ethylene-based polymer; 0 to 40 wt% of an alkyl acrylate, based on the total wt% of monomers present in the second ethylene acid copolymer; and 2 to 15 weight percent of unsaturated dicarboxylic acid monomer, based on the total weight percent of monomers present in the second ethylene acid copolymer. The ratio of the first ethylene acid copolymer to the second ethylene acid copolymer in the ionomer is 90/10 wt% to 10/90 wt%. At least 70 mole% of the total acid units in the ionomer are neutralized, and 10 to 70 mole% of the total acid units of the blend are neutralized by magnesium cations.

Detailed Description

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. In case of conflict, the present specification, including definitions, will control.

Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of various embodiments, suitable methods and materials are described herein.

All percentages, parts, ratios, etc., are by weight unless otherwise specified. When an amount, concentration, or other value or parameter is given as either a range, preferred range, or a list of lower preferable values and upper preferable values, this is to be understood as specifically disclosing any pair formed from any lower range limit or preferred value and any upper range limit or preferred value, regardless of whether ranges are separately disclosed. Unless otherwise indicated, when numerical ranges are recited herein, the ranges are intended to include the endpoints thereof, and all integers and fractions within the ranges. It is not intended that the scope of the invention be limited to the specific values recited when defining a range.

When the term "about" is used to describe a value or an endpoint of a range, the disclosure should be understood to include the specific value or endpoint referred to.

As used herein, the terms "comprises," "comprising," "includes," "including," "contains," "characterized as," "having," "has/having," or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Further, unless expressly stated to the contrary, "or" means an inclusive or and not an exclusive or.

The transitional phrase "consisting essentially of" limits the scope of the claims to the specified materials or steps and those materials or steps that do not materially affect one or more of the basic and novel features of the disclosure. Where applicants have defined an embodiment, or a portion thereof, in open-ended terms such as "comprising," this specification should be construed to also use the term "consisting essentially of," to describe such an embodiment, unless otherwise noted.

The use of "a/an" is used to describe elements and components of various embodiments. This is for convenience only and gives a general sense of the various embodiments. This description should be read to include one or at least one and the singular also includes the plural unless it is obvious that it is meant otherwise.

The term "polymer" refers to a polymeric compound prepared by polymerizing monomers, whether of the same or different type. Thus, the generic term polymer embraces the terms "homopolymer" and "copolymer". The term "homopolymer" refers to a polymer prepared from only one type of monomer; the term "copolymer" refers to a polymer prepared from two or more different monomers, and for purposes of this disclosure, may include "terpolymers" and "interpolymers".

The term "monocarboxylic acid monomer" refers to a molecule having a reactive moiety, such as a vinyl or vinylidene group, which can bond to other monomers to form a polymer and a carboxylic acid (-c (o) OH) moiety not included in the reactive moiety. For example, (meth) acrylic acid is a monocarboxylic acid monomer in which a vinylidene group is the reactive moiety and a carboxylic acid is present. The term "(meth) acrylic" includes methacrylic and/or acrylic, and "(meth) acrylate" includes methacrylate, acrylate, or a combination of methacrylate and acrylate.

The term "unsaturated dicarboxylic acid monomer" as used in this disclosure refers to a molecule having a reactive moiety (such as a vinyl or vinylidene group) that can bond to other monomers to form a polymer and two carboxylic acid (-c (o) OH) moieties that are not included in the reactive moiety. In addition, "unsaturated dicarboxylic acid monomer" includes dicarboxylic acid derivative monomers (half esters and anhydrides).

Various embodiments relate to ionomers having improved creep resistance, including neutralized blends of ethylene acid copolymers. The ethylene acid copolymer comprises the polymerization reaction product of ethylene, a monocarboxylic acid monomer, and an unsaturated dicarboxylic acid monomer. In the ionomer, 10% to 70% of the total acid units of the ethylene acid copolymer are neutralized by magnesium cations. The ionomer having improved creep resistance exhibits a dimensional change of less than 25% at a temperature of 100 ℃ over a 30 minute period at 20 psi. In one or more embodiments, the ionomer exhibits a dimensional change of less than 25%, less than 20%, less than 15%, less than 10% at 20psi for 30 minutes at 100 ℃.

In one or more embodiments, the ethylene acid copolymer is the polymerization product of ethylene, a monocarboxylic acid monomer, and an unsaturated dicarboxylic acid monomer. The monocarboxylic acid monomers can include, for example, one or more of acrylic acid, methacrylic acid, or a combination thereof.

In one or more embodiments, the monocarboxylic acid monomer can be present in an amount of 2 to 20 weight percent, based on the total weight of monomers present in the ethylene acid copolymer. All individual values and subranges subsumed "from 2 to 20 weight percent" are disclosed as separate examples. For example, the monocarboxylic acid monomer can be present in an amount of 5 to 15 weight percent, 3 to 19 weight percent, or 4 to 10 weight percent based on the total weight of monomers present in the ethylene acid copolymer.

In one or more embodiments, the amount of unsaturated dicarboxylic acid monomer can be 2 to 15 weight percent unsaturated dicarboxylic acid monomer based on the total weight percent of monomers present in the ethylene acid copolymer. All individual values and subranges subsumed "from 2 to 15 weight percent" are disclosed as separate examples. For example, the unsaturated dicarboxylic acid monomer can be present in an amount of 5 to 15 weight percent, 3 to 10 weight percent, or 4 to 10 weight percent, based on the total weight of monomers present in the ethylene acid copolymer. In embodiments, the dicarboxylic acid may include maleic anhydride, monomethyl maleate, monoethyl maleate, monopropyl maleate, monobutyl maleate, or combinations thereof.

In embodiments of the ionomers of the present disclosure, the ionomer may include a blend of two polymer resins, a first ethylene acid copolymer and a second ethylene acid copolymer. One of the first ethylene acid copolymer or the second ethylene acid copolymer contains an unsaturated dicarboxylic acid monomer.

In one or more embodiments, the ionomer can include a neutralized blend of a first ethylene acid copolymer and a second ethylene acid copolymer. In one or more embodiments, the ratio of the first ethylene acid copolymer to the second ethylene acid copolymer is from 90/10 wt% to 10/90 wt%. In various embodiments, the neutralized blend includes from 60 to 90 weight percent of the first ethylene acid copolymer or from 60 to 80 weight percent of the first ethylene acid copolymer, based on the total weight of the blend. In some embodiments, the neutralized blend includes 60 to 90 weight percent of the second ethylene acid copolymer or 60 to 80 weight percent of the second ethylene acid copolymer, based on the total weight of the blend.

Ionomers of the present disclosure can include 10 to 60% of the total acid units of the blend neutralized with magnesium cations. In some embodiments of the ionomer, 20% to 50%, 20% to 60%, 25% to 60%, or 30% to 55% of the total acid units of the blend are neutralized by magnesium cations.

In various embodiments, the first ethylene acid copolymer is the polymerization reaction product of: ethylene; 2 to 20 weight percent monocarboxylic acid, based on the total weight percent of monomers present in the first ethylene acid copolymer; and 0 to 40 weight percent of an alkyl acrylate, based on the total weight percent of monomers present in the first ethylene acid copolymer.

In one or more embodiments, the second ethylene acid copolymer is the polymerization reaction product of: ethylene; 0 to 20 wt% monocarboxylic acid, based on the total wt% of monomers present in the second ethylene acid copolymer; 0 to 40 wt% of an alkyl acrylate, based on the total wt% of monomers present in the second ethylene acid copolymer; and 2 to 15 weight percent of unsaturated dicarboxylic acid monomer, based on the total weight percent of monomers present in the ethylene acid copolymer.

In one or more embodiments, the monocarboxylic acid monomer can be present in the first ethylene acid copolymer or the second ethylene acid copolymer in an amount of 0 wt.% to 20 wt.%, based on the total weight of monomers present in the ethylene acid copolymer. All individual values and subranges from "0 to 20 weight percent" are disclosed as separate embodiments. For example, the monocarboxylic acid monomer can be present in an amount of 2 to 20 weight percent, 5 to 30 weight percent, or 4 to 10 weight percent based on the total weight of monomers present in the ethylene acid copolymer.

In one or more embodiments, the amount of unsaturated dicarboxylic acid monomer in the second ethylene acid copolymer can be 2 to 15 weight percent unsaturated dicarboxylic acid monomer based on the total weight percent of monomers present in the ethylene acid copolymer. All individual values and subranges subsumed "from 2 to 15 weight percent" are disclosed as separate examples. For example, the unsaturated dicarboxylic acid monomer can be present in an amount of 5 to 15 weight percent, 3 to 10 weight percent, or 4 to 10 weight percent, based on the total weight of monomers present in the second ethylene acid copolymer. In embodiments, the dicarboxylic acid may include maleic anhydride, monomethyl maleate, monoethyl maleate, monopropyl maleate, monobutyl maleate, or combinations thereof.

In various embodiments, the first ethylene acid copolymer or the second ethylene acid copolymer can include an alkyl acrylate. In some embodiments, the first ethylene acid copolymer further comprises from 0 wt% to 40 wt% of an alkyl acrylate, based on the total weight of monomers present in the ethylene acid copolymer. All individual values and subranges from "0 to 40 weight percent" are disclosed as separate embodiments. The first ethylene acid copolymer or the second ethylene acid copolymer may comprise, for example, 1 to 30 wt% of the alkyl acrylate. The alkyl acrylate may be, for example, but not limited to, ethyl acrylate, methyl acrylate, n-butyl acrylate, isobutyl acrylate, or combinations thereof. In various embodiments, the alkyl acrylate has an alkyl group of 1 to 8 carbons. This is referred to as C2-C8 alkyl acrylate. In a particular embodiment, the alkyl acrylate is n-butyl acrylate.

In one or more embodiments of the ethylene acid copolymer, the first ethylene acid copolymer, or the second ethylene acid copolymer, the unsaturated dicarboxylic acid monomer comprises a reaction product of a precursor acid copolymer of a dicarboxylic acid or a derivative of a dicarboxylic acid. The unsaturated dicarboxylic acid monomer may include maleic acid, itaconic acid, fumaric acid, monoethyl maleate (MAME), monopropyl maleate, monoethyl maleate, monobutyl maleate, or combinations thereof; and C of these acids₁-C₄Alkyl half esters, and anhydrides of these acids, including maleic anhydride, monomethyl maleic anhydride, monoethyl maleic anhydride, and itaconic anhydride. In some embodiments, the unsaturated dicarboxylic acid monomers may include, but are not limited to, maleic anhydride, ethyl hydrogen maleate, and methyl hydrogen maleate. The carboxylic acid or anhydride units of these monomers can be neutralized by metal ions, as though shown by the monocarboxylic acid units, the neutralization of unsaturated dicarboxylic acid monomers can differ in their properties and impact on polymer characteristics, including melt behavior. The dicarboxylic acid may be dehydrated to form intra-chain anhydride units (i.e., intra-chain, rather than cross-linked inter-chain anhydride units) within the polymer.

In various embodiments of the ethylene acid copolymer, the first ethylene acid copolymer and the second ethylene acid copolymer can comprise at least 60 wt% of monomers derived from ethylene. All individual values and subranges subsumed under "60 weight percent" are disclosed herein as separate embodiments; for example, the ethylene acid copolymers, first ethylene acid copolymers, and second ethylene acid copolymers of the present disclosure can comprise at least 60 wt% of units derived from ethylene; at least 70% by weight of units derived from ethylene; at least 80% by weight of units derived from ethylene; or from 60 to 95 weight percent of units derived from ethylene; or from 80 to 98 wt% of units derived from ethylene.

Ionomers of the present disclosure include neutralized blends of ethylene acid copolymers or neutralized blends of a first ethylene acid copolymer and a second ethylene acid copolymer. The term "neutralized blend" includes fully or partially neutralized ethylene acid copolymers. The ethylene acid copolymer may contain neutralized and unneutralized monocarboxylic acid units; neutralized, mono-neutralized and non-neutralized dicarboxylic acid units and intrachain anhydride units.

When referring to the total acid units neutralized, the monocarboxylic acid provides one acid unit; the dicarboxylic acid provides two acid units; anhydrides such as maleic anhydride are believed to provide two acid units; and the half-ester is believed to provide one acid unit. The percent neutralization is calculated based on the number of acid units considered above as well as the number of metal equivalents added. In fact, the anhydride units may remain as anhydride units rather than becoming acid units. When neutralized, the anhydride monomer units may form bimetallic salts, monometallic salts; forming unneutralized unsaturated dicarboxylic acid monomers; or to leave the anhydride units unchanged as anhydride units as if it had no acid functionality. While the half ester of an unsaturated dicarboxylic acid monomer is counted as only one acid, it can actually be converted to an unsaturated dicarboxylic acid monomer or anhydride, with the various possibilities described above in connection with neutralization. However, as noted above, regardless of how many acid groups (free or neutralized) are actually present, the percent neutralization is calculated as the number of acid units based on the known moles of monocarboxylic and dicarboxylic acid comonomers. In view of the various mutations and possible salts of the unsaturated dicarboxylic acid monomers, the actual percentage of neutralized acid groups as a percentage of the total number of actually neutralized and unneutralized free acid groups may therefore differ from the calculated percent neutralization, the latter being based on the monocarboxylic acid monomer or the unsaturated dicarboxylic acid monomer in the ionomer. The difference is due to the anhydride unit, which is not an acid unit, but is counted as two acid units.

In some embodiments, the ionomer may include cations other than Mg cations and Mg cations in the blend. The blend may be neutralized by at least one additional cation of a neutralizing salt. The neutralizing salt of the at least one additional metal cation may be selected from the group consisting of zinc, lithium and sodium salts. In some embodiments, the ionomer may include 0% to 10%, 1% to 10%, 5% to 20%, 5% to 30%, or 10% to 50% of the total acid units of the blend neutralized with sodium cations of a neutralizing salt, lithium cations of a neutralizing salt, zinc cations of a neutralizing salt, or a combination thereof.

In various embodiments, the ionomers exhibit improved creep resistance at high temperatures while retaining their resilience and foamability.

Ethylene acid copolymers can be prepared by standard free radical copolymerization processes operating in a continuous manner using high pressure. The monomers are fed to the reaction blend in a ratio which is related to the reactivity of the monomers and the amount desired to be incorporated. In this way, a uniform, nearly random distribution of monomer units along the chain is achieved. Unreacted monomer can be recycled. Additional information regarding the preparation of ethylene acid copolymers comprising alkyl acrylate monomers can be found in U.S. Pat. No.3,264,272 and U.S. Pat. No. 4,766,174, each of which is incorporated herein by reference in its entirety.

The blend may be produced by any method known to those skilled in the art. It is substantially melt processable and can be prepared by combining one or more ethylene acid copolymers or ionomers of ethylene acid copolymers, one or more fatty acids or salts thereof, a basic metal compound, and a neutralizing composition comprising a trivalent metal cation to produce a mixture and heating the mixture under conditions sufficient to produce the composition. The heating may be carried out at a temperature in the range of 80 ℃ to 350 ℃, 120 ℃ to 300 ℃, or 160 ℃ to 260 ℃, under a pressure that accommodates the temperature for a period of 30 seconds to 2 hours or 3 hours. The blends can be prepared by melt blending the ethylene acid copolymer and/or ionomer thereof with one or more fatty acids or salts thereof and simultaneously or subsequently combining a sufficient amount of the basic metal compound and the trivalent metal cation. Salt blends of the components may be prepared or the components may be melt blended in an extruder. For example, the ethylene acid copolymer and organic acid (or salt) can be simultaneously mixed and processed with the metal compound using a Werner & Pfleiderer twin screw extruder.

The blend may additionally include minor amounts of additives including plasticizers, stabilizers (including viscosity stabilizers, hydrolytic stabilizers), primary and secondary antioxidants, ultraviolet light absorbers, antistatic agents, dyes, pigments or other colorants, inorganic fillers, flame retardants, lubricants, reinforcing agents (such as glass fibers and flakes), synthetic (e.g., aramid) fibers or pulps, blowing or bubbling agents, processing aids, slip agents, anti-blocking agents (such as silica or talc), mold release agents, tackifying resins, or combinations of two or more thereof. Inorganic fillers such as calcium carbonate may also be incorporated into the blend.

These additives may be present in the blend in an amount in the range of 0.01 to 40 weight percent, 0.01 to 25 weight percent, 0.01 to 15 weight percent, 0.01 to 10 weight percent, or 0.01 to 5 weight percent. Incorporation of the additives can be carried out by any known method, for example by dry blending, by extruding a mixture of the various ingredients, by conventional masterbatch techniques and the like.

In some embodiments, ionomers according to the present disclosure exhibit load bearing capacity at temperatures above the melting temperature of the ionomer as measured by Differential Scanning Calorimetry (DSC).

According to various embodiments, the ionomer may be used to form a foam or a molded article. For example, in embodiments, the ionomer may be combined with additives for controlling foam properties to form foams of various shapes. In some embodiments, the foam may be extruded, such as from a twin screw extruder as known to one of ordinary skill in the art.

The blowing agent used to make the foam (also referred to as a blowing agent) may be a physical blowing agent or a chemical blowing agent. As used herein, a "physical blowing agent" is a low boiling liquid that volatilizes under curing conditions to form a bubbling gas. Exemplary physical blowing agents include hydrocarbons, fluorocarbons, hydrofluorocarbons, hydrofluoroolefins, hydrochlorofluoroolefins, and other halogenated compounds. Other suitable chemical blowing agents may include, for example, sodium bicarbonate, ammonium bicarbonate, azodicarbonamide, dinitrosopentamethylenediamine, and sulfonyl hydrazide. Blowing agents such as water or carbon dioxide added as a gas or liquid or generated in situ by the reaction of water with the polyisocyanate may also be used. The foaming agent may be used in a mixture of two or more, and chemical and physical foaming agents may be used together to adjust the expansion-decomposition temperature and the foaming process.

The foam composition may further include a free radical initiator or cross-linking agent, a co-curing agent, an activator, and any other type of additive typically used in similar compositions, including but not limited to pigments, adhesion promoters, fillers, nucleating agents, rubbers, stabilizers, and processing aids.

The free radical initiator or crosslinking agent may include, but is not limited to, by way of example and not limitation, organic peroxides, such as dialkyl organic peroxides. Examples of suitable organic peroxides include 1, 1-di-tert-butylperoxy-3, 3, 5-trimethylcyclohexane, tert-butylcumyl peroxide, diisopropylphenyl peroxide, 2, 5-dimethyl-2, 5-di (tert-butyl-peroxy) hexane, 1, 3-bis (tert-butyl-peroxy-isopropyl) benzene, or a combination of two or more thereof.

The co-curing agent comprises trimethylpropane triacrylate (and similar compounds), N-m-phenylene bismaleimide, triallyl cyanurate, or a combination of two or more thereof.

The activator may comprise an activator for blowing agents and may comprise one or more metal oxides, metal salts or organometallic complexes. Examples include ZnO, zinc stearate, MgO, or a combination of two or more thereof.

Foams can be produced by a number of methods, such as compression molding, injection molding, or a combination of extrusion and molding. The method may include mixing the components of the foam composition under heating to form a melt. The components may be mixed and blended using any technique known and used in the art, including Banbury (Banbury), intensive mixers, two-roll mills, and extruders. The time, temperature, shear rate can be adjusted to ensure dispersion without premature crosslinking or foaming.

After mixing, shaping can be carried out. A sheet roll or calender roll may be used to make a sheet of appropriate size for foaming. An extruder may be used to shape the composition into pellets.

The foaming may be carried out in a compression mould at a temperature and for a time to complete the decomposition of the peroxide and blowing agent. The pressure, molding temperature and heating time can be controlled. Foaming can be performed using injection molding equipment by using particles made of the foam composition. The resulting foam may be further shaped to the dimensions of the finished product by any means known in the art, including thermoforming and compression molding.

In various embodiments, the resulting polymer foam composition may be substantially closed cell and may be used in a variety of articles, such as footwear applications, including midsoles or insoles.

In one or more embodiments, the molded article exhibits a dimensional change of less than 25%, less than 20%, less than 15%, less than 10% at 20 ℃ in 30 minutes under stress at 100 psi.

The ionomers of this invention can be prepared by standard neutralization techniques, as disclosed in U.S. patent No.3.264.272 (Rees), which is incorporated herein by reference. The MI of the compositions of the present disclosure may be from 0.01 to 100 grams/10 minutes, preferably from 0.1 to 30 grams/10 minutes, according to ASTM D-1238, using a 2160 gram weight, of the resulting ionomer measured at 210 ℃. In one or more embodiments, the ionomer has a density of 0.920 to 0.980 g/cc.

The ethylene acid copolymers, first ethylene acid copolymers, and second ethylene acid copolymers of the present disclosure can be prepared by standard free radical copolymerization processes operating in a continuous manner using high pressure. The monomers are fed to the reaction blend in a ratio related to the reactivity of the monomers and the amount desired to be incorporated. In this way, a uniform, nearly random distribution of monomer units along the chain is achieved. Polymerization in this manner is well known and is described in U.S. patent No. 4.351.931 (Armitage), which is incorporated herein by reference. Other polymerization techniques are described in U.S. Pat. No. 5,028,674 (Hatch et al) and U.S. Pat. No. 5,057,593 (Statz), which are also incorporated herein by reference.

Examples of the invention

Test program

Melt Index (MI) was measured using an ASTM D-1238, using a 2160 gram weight.

Melting points (Tm) were measured using Differential Scanning Calorimetry (DSC). Differential scanning calorimetry was measured on a TA instruments Q1000DSC equipped with an RCS cooling attachment and an autosampler. Melting points (Tm) of the samples were measured according to ASTM D3418.

The composition of the ionomer was determined using a Perkin Elmer fourier transform infrared spectrometer (FTIR). A compression molded film having a thickness of 5 mils was used for FTIR analysis.

The following examples are provided to illustrate various embodiments and are not intended to limit the scope of the claims. All parts and percentages are by weight unless otherwise indicated. The following provides approximate characteristics, features, parameters, and the like regarding various working examples, comparative examples, and materials used in the working and comparative examples. Further, the description of the raw materials used in the examples is as follows:

example 1 creep resistance of ethylene acid copolymer

Creep resistance varies with time, temperature and weight loaded (stress). A simple test was used to distinguish the creep resistance of ionomers with and without dicarboxylic acid comonomer MAME under neutralization with various metal cations with or without MAME. Creep tests were performed by measuring the dimensional change (vertical) of film samples with attached empty load in a cross-flow air oven with a rack to hold the sample rack. Creep testing was performed on 10 mil thick, 1 inch wide, 3 inch long strips of compression-molded film cut from the compression-molded film. The film was suspended under an empty load of 100 grams and the oven was initially set to 100 ℃. The deformation of the film sample was measured after 30 minutes of standing in the oven. The oven temperature was then raised to 120 ℃ for testing.

The results summarized in table 1 include data from inventive examples 1.1 to 1.2, comparative terpolymer examples CT 1.1 to CT 1.4, and comparative copolymer examples CC 1.1 to CC 1.3. The polymer compositions in examples 1.1 to 1.2 are ethylene/methyl acrylate/monoethyl maleate (E/MAA/MAME) terpolymers neutralized with magnesium metal cation (Mg). Inventive examples 1.1 to 1.2, comparative trimer examples CT 1.1 to CT 1.4, are ionomers neutralized to different degrees of neutralization with different metal cations based on E/MAA/MAME (73/11/6 wt%) with an MI of about 100g/10 min, as measured according to ASTM D1238 at 190 ℃, using 2.16 kg.

The polymer compositions of comparative CC 1 to CC 3 included E/MAA neutralized with Na, Zn and Mg cations (85/15 wt%). The melting temperature of the sample is reported. Creep resistance testing was performed in a cross-flow air oven with a rack to hold specimen holders. Each sample was a test specimen in the form of a film 10 mils (one mil-1/1000 inches) thick, 3 inches long, 1 inch wide, under an air load of 100 grams. The film falls to the bottom of the furnace due to loss of load bearing capacity.

Table 1: creep resistance of ionomer samples

The results in table 1 show that the Na, Zn and Mg neutralized samples of comparative CC 1.1 to CC 1.3 all failed at 100 ℃. For film samples that fall to the bottom of the furnace by losing any load bearing capacity, they are considered to fail the creep test at 100 ℃ (a temperature above the melting temperature of the sample). The ionomer sample is expected to lose load bearing capacity at temperatures above its melting temperature. Comparison CT 1.1 to CT 1.4 (which include Na, Li, Zn and Na/Zn cations to neutralize the acid E/MAA/MAME trimer) failed at 100 ℃. The results in example 1.1 show that the Mg ionomer of the E/MAA/MAME trimer passes the creep test at 100 ℃. The results of example 1.2 show that Mg (40% neutralized) passes the creep test at 100 ℃ and 120 ℃. According to the results in table 1, Mg ionomers comprising acid terpolymers of EE/MAA/MAME have better physical properties than those Na, Zn, Li or Na/Zn ionomer samples. In examples 1.1 and 1.2, Mg ionomers are the only resins that have creep resistance above the melting point of the sample.

Example 2 creep resistance of ionomer blends

The results are blends of various ionomer samples of E/MAA/MAME terpolymers and E/MAA copolymers, as summarized in table 2. The blends were prepared in a 26mm twin extruder with mixing screws using melt temperatures between 220 ℃ and 250 ℃. Creep temperature is defined as the deformation of the film to 25% strain at a load of 110 grams.

Examples 2.1. to 2.6 include polymeric resin blends of ethylene acid copolymer a, ethylene acid copolymer B, and ethylene acid copolymer C.

Ethylene acid copolymer a ("polymer a") is a Mg ionomer of an ethylene acid copolymer comprising the polymerization reaction product of ethylene and 15 wt% methacrylic acid, wherein 50 mol% of the nominal total acid units are neutralized by Mg cations. The Melt Index (MI) of the ionomer was 0.8g/10 min as measured according to ASTM D1238 at 190 ℃, 2.16 kg.

Ethylene acid copolymer B ("polymer B") is a Zn ionomer of an ethylene acid copolymer comprising the polymerization reaction product of ethylene, 11 wt% methacrylic acid, and 6 wt% monoethyl maleate, wherein 50% of the nominal total acid units are neutralized by zinc cations. The MI of the ionomer was 1.0g/10 min as measured according to ASTM D1238 at 210 ℃, 2.16 kg.

Ethylene acid copolymer C ("polymer C") is a Mg ionomer of an ethylene acid copolymer comprising the polymerization reaction product of ethylene, 11 wt% methacrylic acid, and 6 wt% monoethyl maleate, wherein 18% of the nominal total acid units are neutralized by zinc cations. The MI of the ionomer was 1.1g/10 min as measured according to ASTM D1238 at 210 ℃, 2.16 kg.

Table 2: creep resistance of ionomer blends

The results in table 2 show that examples 2.2, 2.5 and 2.6 containing both MAME and Mg cations achieve creep resistance above their melting temperature. The ionomers in examples 2.2, 2.5 and 2.6 contain MAME and Mg cations. Since the polymer in these examples is the only polymer that has creep resistance at temperatures above the melting temperature, it is believed that the MAME content and Mg content act synergistically to increase creep resistance. Thus, the data show that Mg cation content and MAME content are two variables that result in higher creep resistance.

The creep test of table 2 was performed by measuring the dimensional change (vertical) of the film sample with attached empty load in a cross-flow air oven with a rack to hold the sample rack. Creep testing was performed on 10 mil thick, 1 inch wide, 3 inch long strips of compression-formed film cut from 10 mil thick compression-formed film. The film was suspended under an empty load of 110 grams and the oven was initially set to 80 ℃. The deformation of the film sample was measured after being placed in the oven for 30 minutes, and then the oven temperature was raised to 10 ℃. Creep temperature was determined when the film sample reached 25% strain deformation.