JP2000017084A - Stepwise condensation and dynamic vulcanization to prepare plastic/rubber blend which is not substantially plasticized - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a relatively soft blend with a specific shore D hardness obtained by preparing in steps, successive a vulcanized blend of an engineering thermoplastic resin and at least two kinds of curable acrylic rubber. SOLUTION: A blend with below 30 of shore D hardness is prepared. In the presence of a second curable rubber which is not reacted with a first curing agent, the first curable rubber is cured with a first curing agent to prepare a first vulcanized rubber while removing a gas discharged. Then, in the presence of an engineering thermoplastic resin and the first vulcanized rubber, the second curable rubber is cured with a second curing agent by a condensation reaction while removing a gas discharged and a sufficiently precise intermediate hard blend with at least 40 of shore D hardness is prepared. Thereafter, in the presence of the intermediate hard blend, additional curable rubber is cured with an additional curing agent by a condensation reaction while removing a gas discharged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION This invention is a continuation-in-part of U.S. Patent Application No. 08-686,782 and U.S. Patent Application No. 08-686,798 filed July 26, 1996.

"Thermoplastic vulcanizates" or "TPVs"
(Formerly "thermoplastic elastomers" or "TPEs"
Polymer blends, which have a combination of elasticity and thermoplasticity (referred to as the so-called), are produced by dynamic vulcanization to have the desired hardness / softness, oil and temperature resistance, oxidation resistance, and processability, among others. Is done. For thermoplastic elastomers that are not physical blends, the properties are:
Depending on the relative amounts provided by each of the "hard" and "soft" phases, and the properties of each phase. For economic value, the hard phase is typically provided by readily available engineering thermoplastics and is commonly referred to simply as "plastic". Most commonly, the plastic is selected from polyesters, polyamides, and polyolefins that provide a continuous phase of a hard phase, in which there are dispersed regions of the "soft" phase of the elastomer. TPVs containing polyolefins are not the subject of the present invention, the present invention relates to other "plastic" TPVs,
Combined with a vulcanizable (herein simply referred to as "curable") rubber to provide a relatively "soft" blend of controlled hardness (Shore D less than 30). Such blends are exceptionally resistant to oil swell and compression set.

[0003]

SUMMARY OF THE INVENTION Dispersed "polar rubber"
In a market requiring a blend of polar engineering thermoplastics containing a phase and a continuous "plastic" phase, the "rubber" phase is present in a major proportion by weight relative to the "plastic" phase and the blend is low Oil swell and hardness ranging from Shore A30 to Shore D30. In particular, there is a need for blends having a Shore A of 60 to 90. Such "polar rubber / plastic" blends of polyamide and acrylic rubber, or polyester and acrylic rubber, are too viscous to be manufactured in conventional equipment and are substantially plastic, even if the actual blend is manufactured. Is not converted. That is, if it contains more than 30 parts by weight of plasticizer, the blend is not useful. "Not useful" means that the plasticizer exudes from the blend at the processing temperature, typically 250 ° C, and also exudes at ambient temperature. Useful pellets must have a specific gravity in the range of 0.9 to 1.2 and are not porous (or spongy). This is confirmed by the fact that the pellets have a particularly high moisture content, even if they have been dried for an extended period. In particular, blends with polyolefins
It can be severely plasticized and has significant value. However, vulcanized blends of acrylic rubber with nylon, PBT, and a huge variety of other non-polyolefins do not reach desirable products unless they contain substantial plasticizers or compatibilizers. By "substantially free" is meant that the blend has less than 30 parts by weight of plasticizer per 100 parts by weight of rubber. Where the curable acrylic rubber is present in the majority of the weight (ie, "rubber-rich"), prior art methods produce undesirable, porous blends. Curable functional groups (or reactive sites)
Acrylic rubbers containing recurring units derived from a monoolefinically unsaturated monomer having no, such as ethylene methyl acrylate copolymer, are not "curable rubbers" as the term is used herein. A sufficiently dense but desirably soft and rubbery blend, with a small portion of the weight being the "plastic phase" and the majority being the "curable rubber phase" (this blend has excellent tensile strength, compression It is an object of the present invention to provide a method for producing permanent set and oil swell resistance). "Sufficiently dense" means essentially free of porosity as measured. If pelletized, the specific gravity of the pellet is the same as the article formed from the pellet.

[0004]

BACKGROUND OF THE INVENTION Polar blends are made by dynamic vulcanization using condensation reactions with the release of small molecules, but such reactions involve the addition of olefin rubber and polyolefin thermoplastics. Relatively slow compared to dynamic vulcanization. Conducting the condensation reaction below a certain temperature in the presence of sufficient plasticizer to promote blending of the components, since temperatures below this will have a detrimental effect on the physical properties of the blend. Can not. If the released small molecule is not processed, it is packed as a sponge-like mass into the blend. Accordingly, such blends are preferably made in a substantially continuous process using a suitable exhaust system, which operates at the required temperatures in the range of about 200 ° C to 275 ° C, Banbur (Banbur) to add the components in stages and remove the reaction products.
This is because it is not practical to sufficiently seal the batch mixer as in y). Blends were also prepared in separate and distinct stages, using relatively short mixed reaction zones that were originally long, and dynamically vulcanized in each stage before introducing the pellets to the next stage. Pelletizing the blend is generally very expensive.

[0005] While different lengths of continuous mixer or mixing extruder barrels are available, commercially available barrels have a ratio of length (L) to diameter (D) of 80.
Does not exceed. They typically range from about 20 to 80. Thus, for all practical purposes, a continuous process for producing a blend must be completed in a barrel with an L / D not exceeding 80, with an L / D close to 20 barrels If a method is provided for removing small molecules released for a continuous condensation reaction, the method can be performed in two or more separation steps.

[0006] A process for producing blends having a non-polyolefinic "plastic" is disclosed in Horrio
n) U.S. Pat. Nos. 5,589,544 and 08-686,782 and 08-686,798 filed Jul. 26, 1996. “Non-polyolefin” plastics
It means that the plastic is substantially free of polyolefin chains. The term "plastic" refers to polyamide, polycarbonate, polyester, polysulfonate, polyactone, polyacetal, acrylonitrile-butadiene-styrene (ABS), polyphenylene oxide (PPO), polyphenylene sulfide (PPS), styrene-acrylonitrile (SAN), Polyimide, styrene
Refers to a resin selected from the group consisting of maleic anhydride (SMA) and aromatic ketone, any of which may be used alone or in combination with others. Most preferred engineering resins are polyamides and polyesters.

In US Pat. No. 5,589,554 to Horion, in a first step, a cured rubber concentrate (CR
C) is prepared and blended in a second stage with substantially engineering thermoplastics, optionally with a compatibilizer. CRCs are formed from a mixture of a curable plastic acrylic copolymer ("rubber") and an acrylic "polymer carrier" that does not react with a curing agent for rubber.
Rubber is immiscible with the polymeric carrier.

Referring to FIG. 1, US Pat. No. 5,589,554
1 schematically illustrates a mixing (discharging) barrel of an extruder in which the two-stage process of No. 1 is performed continuously. Feed a mixture of curable rubber 1 and curable rubber 2 (hereinafter "carrier") to the first stage of the extruder, along with a curing agent for curable rubber 1 and optionally an additive that may include a compatibilizer The mixture is then dynamically vulcanized (US Pat. No. 5,589,554, column 7, line 51 to column 8, line 11). CRC (blend A) is formed because only the curable rubber 1 is cured. In the second step, the CRC is blended with the plastic and, if necessary, additional additives and compatibilizers (column 8, lines 57 to 6).
7 lines). While mixing with the plastic using a different curing agent than that used to cure the curable rubber,
The carrier can be crosslinked (col. 9, lines 1-5). However, plastic blends (blends formed directly in the second stage)
H) tends to be porous, as described in Horion U.S. Pat. No. 5,589,554. Porous (sponge-like) pellets of Blend H are trapped in water in the pelletizing step and difficult to handle in the continuous processing step. It is not practical to dry such wet pellets before continuous processing. If an extruder is used and the blend is formed at the desired plastic to rubber ratio, the pellets that are not suitable for injection molding will trap water in order to form a relatively soft TPV.

[0009] The 08-686798 application discloses a first curable acrylic rubber and a curable acrylic rubber in the presence of a curative and plastic to form a blend having a single low brittle temperature (LTB). A method for vulcanizing a terpolymer is disclosed. The 08-686,782 application discloses a method for crosslinking at least a first and a second curable acrylic rubber (each having a different functional group) in a plastic substantially without the influence of a vulcanizing agent. . Curable rubbers are compatible with each other and with engineering plastics. By "compatible" is meant that the rubber forms a mixture in which the second phase can coexist with the continuous phase without the use of plasticizers or surfactants. Typical acrylic rubbers, C ₂ to C ₃ olefins,
C ₁ -C in combination with one or more groups selected from carboxyl, hydroxyl, epoxy, halogen and the like
_{It has 10} alkyl groups.

The final blend has a Shore D of less than 30,
The first hardenable acrylic resin is used to form an intermediate hardblend first, and secondly within the intermediate hardblend, with substantially no plasticizer so as to preferably have a Shore A of less than 90. It is not known how to use a three-step process involving successive first and second condensation reactions to form a second cured blend with another curable acrylic rubber. The first curable rubber contains a different functional group than the second curable rubber.

As can be seen by the comparative examples set forth below, the blend of US Pat. No. 5,589,554 has components present in similar relative amounts as the blends prepared by the three-step process of the present invention. United States Patent No.
Blends produced by the two-step process taught in 5,589,554 have surprisingly different properties.

[0012]

SUMMARY OF THE INVENTION The above-mentioned US Pat. No. 5,589,
No. 554 and 08-686798, polar engineering thermoplastics (briefly referred to as "plastics").
That the composition comprises at least two curable rubbers blended with the compound can be manufactured to have sufficiently dense and controlled physical properties in a three-step process including an intermediate processing step. It's been found. The key intermediate stage results in only the first curable rubber being cured, forming a sufficiently dense intermediate hard blend with a Shore D greater than 40. The intermediate hard blend is
In the third stage, the second curable rubber provides a microstructure that can undergo further controlled improvements when cured.

The three-stage process comprises a first and second at least two polar acrylic rubbers each having a repeating unit derived from a monoolefinically unsaturated cross-linking monomer and each having a functional group curable by a different curing agent. Together with blending plastic. That is, each curing agent is effective for one functional group but not the other. Such repeating units of cross-linking monomers are capable of cross-linking polymer chains containing repeating units of acrylate and, if present, non-acrylate copolymerizable monomers. Each rubber is cured by a continuous condensation reaction that releases small molecules. Therefore, small molecules released during the curing of rubber
It is important that they are simultaneously removed from the reaction zone.

[0014] The three-stage process involves a continuous condensation reaction,
It is required to be vulcanized step by step, and in the first step it is necessary to use a sufficient amount of the second rubber to produce a dynamically vulcanized blend in which the rubber is present as a dispersed phase. Required. If only two rubbers are used in the final blend, only a portion of the total amount of the second curable rubber incorporated into the final blend is used in the first stage. In this first stage, in the absence of plastic, the first condensation reaction occurs while the first curable rubber is blended with the second curable rubber, but the first Only the rubber is cured with the first curing agent. Other blends having functional groups susceptible to the same first vulcanizing agent are also cured.

Thus, in the second stage, in the presence of plastic, the second curable rubber present and the second curable rubber present and, if present, the same second hardener are affected. A second condensation reaction occurs by curing other rubbers having susceptible functional groups. Therefore,
The formed intermediate hardblend is sufficiently dense, has a hardness of at least less than 40 Shore D, and can be as high as Shore D80.

In a third step, sufficient additional curable rubber ("third rubber") and additional curing agent ("third curing agent") to provide the desired essentially sufficiently dense final blend. ") Are preferably introduced in combination with the cured first rubber and the uncured second rubber. The third rubber has functional groups, but need not be substantially different from the functional groups of the first or second rubber. The functional group of the third rubber can be the same as the first or second curable rubber functional group, or can be different from either. When the functional group of the third rubber is the same as the second functional group, the second and third curing agents have the same effect, or may have the same effect. The third rubber can be a blend of the first and second rubbers, and the amount of curing agent for each rubber is selected according to the final properties desired for the vulcanized rubber.

Preferably, when the first and second curable rubbers are cured with the first and second curing agents, even if the process is operated continuously step by step in one long reaction zone. , Operated in separate and distinct steps,
An additional amount of the second curable rubber and its vulcanizing agent to provide the desired essentially sufficiently dense final blend,
Introduced in the third stage, optionally in combination with a cured first rubber.

It is preferred to carry out the blending in an axially extending reaction zone, provided that the reaction zone is long enough to simultaneously remove the released (small molecule) gas from the reaction zone. This can be done in one continuous pass, or in two separate passes if the available reaction zone is relatively short to simultaneously remove the gas released in each pass. A typical reaction zone is about 2
Has an L / D ratio in the range of 0 to about 80 and has a Shore A of about 30
Having a controlled hardness in the range of from about 30 Shore D to about 30 Shore A, preferably 40 Shore A to 90 Shore A, and substantially free of plasticizers, typically process oils;
Produce a new final blend. The choice of the L / D ratio and the components of the final blend generally determines whether the method of forming the blend is a continuous or discrete stage.

More specifically, the three-stage vulcanized rubber is a composition of the first rubber that is acted on by the first curing agent in the presence of an initial amount of the second rubber that is not affected by the first curing agent. It is prepared by a first condensation reaction. Preferably, the relative amounts of the first and second rubbers used in the first stage condensation range from 1: 2 to 2: 1. The first condensation releases small molecules such as hydrochloric acid or water and forms a first stage vulcanized rubber. In a second stage, the second rubber is cured by a second curing agent in the presence of a plastic, releasing a second small molecule in a second condensation reaction and having a Shore D of at least less than 40, preferably Is 40
A sufficiently dense intermediate hard blend having a Shore D of ~ 80 is formed. Plastics are a small percentage of the total weight of the first and second rubbers used in the intermediate hard blend. Preferably, in the second stage, the ratio (by weight) of the first and second rubber to plastic is 5
Less than 4, most preferably less than 4 and greater than 1.5. In the third stage, the intermediate hard blend provides a medium in which an additional, controlled amount of additional curable rubber has been cured in a further condensation reaction with an additional curing agent, and the desired, final, Produce a soft blend. Preferably, in the third stage, the ratio of the additional rubber to the plastic, which is the same or different from the first, second and second rubber, is greater than 2, more preferably greater than 3 but less than 5. is there.

Most preferably, the first, second and third stages are continuous in a mixing extruder of sufficient length to facilitate completion of all three stages to remove the final blend. Implemented. However, when limited to extruders of insufficient length for the continuous process, vulcanization recovers the vulcanized rubber of the first stage, preferably in the form of pellets, and then in the second stage, pellets In an extruder to produce an intermediate hard blend, and in a third step, blending the intermediate hard blend with an additional amount of an additional curable acrylic rubber and an additional antioxidant, in a separation step Can be implemented. If the additional rubber, i.e. the third rubber, has a functional group that is cured by a third curing agent different from the first and second curing agents,
All rubbers are preferably selected to be compatible with each other. It is most convenient to use an additional amount of the second rubber as the additional (third) rubber and to use an additional amount of the second curing agent, preferably in combination with the cured first rubber. . Because it is desirable to maintain control over the continuous curing of the rubber, it is not desirable to use rubbers that have functional groups that react with one another to self-cure.

Accordingly, a general object of the present invention is to provide a substantially unplasticized, vulcanized blend of a plastic and a first and a second, at least two, curable acrylic rubber. Providing a stepwise method, wherein (1) forming a first blend of a cured first rubber and an uncured second rubber, and then (2) fully dense The hardness is the total amount of curable rubber present, i.e., the hardness of the mixture in the second condensation reaction when the second rubber is vulcanized with the second curing agent. Controlled by the amount of the first and second curable rubber and curing agent, and then
(3) an additional curable rubber that is different from the first and second rubbers, or is the same as, or a blend of, either the first rubber or the second rubber; and the first and second rubbers. An additional curing agent, different from or identical to the second curing agent, is added to the intermediate hard blend and reacted in a third condensation reaction or continuous with the second condensation reaction; Generate the final blend. Preferably, a continuous condensation reaction is performed in the same long reaction zone.
The properties of the first stage vulcanized rubber are controlled by the relative amounts and reaction conditions of the first and second rubbers in the first stage. The properties of the intermediate hard blend are controlled by the relative amounts of the second rubber to the plastic and the first curable rubber in the second stage and the conditions of the reaction. The properties of the final blend are fine-tuned by the additional curable rubber in the third stage, the controlled addition of additional curing agents, and the conditions of the reaction.

A process for making a relatively soft blend of polyamide and acrylic rubber, such as nylon 6 or its copolyamide, and a blend of polybutylene terephthalate (PBT) or its copolymer and acrylic rubber, wherein the blend comprises: Generally less than 30 Shore D
Having a hardness of 10 as measured by ASTM test D-471.
A plasticizer having an oil swell resistance of less than 150 ° C. and a resistance to compression set of at least 85 after 70 hours, and conventionally used to plasticize conventional, prior art blends or Substantially free of a compatibilizer,
It is a particular object of the present invention to provide a method for making a blend.

[0023]

DETAILED DESCRIPTION OF THE INVENTION Suitable thermoplastic polyamide resins are crystalline or amorphous high molecular weight solid polymers, including homopolymers, copolymers and terpolymers having repeating amide units in the polymer chain. Commercially available polyamides having a Tg or melting point (Tm) higher than 100 ° C. may be used,
Those having a Tm in the range of 80 ° C. are preferred, but rather typically used for forming or operating fibers. Examples of suitable polyamides include polylactams such as nylon 6, polypropiolactam (nylon 3), polyenantiolactam (nylon 7), polycaprylactam (nylon 8), polylauryl lactam (nylon 12), polyaminoundecanoic acid ( Nylon 11), homopolymer of amino acid such as polypyrrolidinone (nylon 4), copolyamide of dicarboxylic acid and diamine such as nylon 6,6, polytetramethylene adipamide (nylon 4,6), polytetramethylene oxa Luamide (nylon 4,2), polyhexamethylene azelamide (nylon 6,9), polyhexamethylene sebasamide (nylon 6,10), polyhexamethylene isophthalamide (nylon 6,1), polyhexamethylene dodecanoic acid (Nylon , 12) and other aromatic and partially aromatic polyamides, copolymers such as caprolactam and hexamethylene adipamide (nylon 6/66), or, for example, nylon 6 / 6,6 / 6,10 Terpolymers, copolymers such as polyether polyamides, and mixtures thereof. Encyclopedia
of Polymer Science and Technology (Kirk & Othmer
Additional examples of suitable polyamides described in J. Am., 2nd Edition, Vol. 11, pp. 315-476, are also incorporated herein in their entirety. Preferred polyamides for use in the present invention are nylon 6, nylon 11, nylon 12, nylon 6,6, nylon 6,9, Knighton 6,10, and nylon 6 / 6,6. Most preferred are nylon 6, nylon 6,6, nylon 11, nylon 12, and mixtures or copolymers thereof. Polyamides generally have a number average molecular weight of from about 10,000 to about 50,000, and preferably from about 30,000 to about 40,000. The amount of polyamide in the blend generally ranges from about 25 to about 1 per 100 parts by weight of total acrylic rubber.
00 parts by weight, desirably about 30 to about 90 parts by weight, and preferably about 35 to about 75 parts by weight.

Suitable thermoplastic polyesters include various ester polymers such as polyesters, copolyesters, or polycarbonates, their monofunctional epoxy end-modified derivatives, and mixtures thereof. The various polyesters can be either aromatic or aliphatic or a combination thereof and generally comprise a diol, such as a glycol having a total of from 2 to 6 carbon atoms, and desirably from about 2 to about 4 carbon atoms; Directly or indirectly derived by the reaction of a fatty acid having a total of 2 to 20 carbon atoms, and preferably about 3 to about 15 carbon atoms, or an aromatic acid having a total of about 8 to about 15 carbon atoms. You. Generally, aromatic polyesters include, for example,
As well as terminal-modified epoxy derivatives such as monofunctional epoxy polybutylene terephthalate, polyethylene terephthalate, polybutylene terephthalate, polyethylene isophthalate, polynaphthalene terephthalate and the like are preferred. Various polycarbonates may be used, as are esters of carboxylic acids. Suitable polycarbonates are based on bisphenol A, ie poly (carbonyldioxy-1,4-phenyleneisopropylidene-1,4-phenylene).

Various ester polymers can also be used to form at least one polyester and a polyether derived from a glycol having 2 to 6 carbon atoms, such as, for example, polyethylene glycol, or an alkylene oxide having 2 to 6 carbon atoms. Also included are block polyesters containing at least one rubbery block, such as polyethers derived therefrom. A preferred block polyester is Hytrel (Hy) available from DuPont.
trel), such as polybutylene terephthalate-b-polyethylene glycol.

Preferably, rather than a plurality of plastics,
For example, only one plastic of one generic class, such as polyamide or polyester, is used and used in small proportions relative to the total amount of rubber in the blend. Preferably the plastic is acrylic rubber 10
It is in the range of about 10 to less than 50 parts, more preferably about 20 to 40 parts per part by weight. If the plastic is largely present in the blend, the hardness is too high,
This results in a blend having a Shore D higher than 30.

Referring to FIG. 2A, an extruder in which the first two steps are performed continuously and continuously is schematically described. In the first stage, a masterbatch of rubber (blend A) is prepared by curing the curable rubber 1 with less than the total amount (used) using a curing agent 1 that cures only the first rubber. It is prepared by blending with natural rubber 2. The first rubber has functional groups that can condense with reactive sites on adjacent chains of the same rubber. If more than one first rubber is used (this is the case because it can be cured with the same first curing agent), the condensation reaction can be either or both (or all the plurality of first) rubbers With the chain of.

The one or more functionalized first and second acrylic rubbers are generally compatible with each other and also with plastics, especially if they are polyamides or polyesters.

In a second stage, a rubber masterbatch (blend A) is blended with the selected plastic and cured with a second hardener (hardener 2). The second curing agent initiates a condensation reaction of the functional groups on the rubber with reactive sites on adjacent chains of the same rubber, producing a sufficiently dense intermediate hard blend. When using multiple second rubbers that are cured with the same second curing agent, the condensation reaction proceeds with either or both (or all of the multiple second) rubber chains.

Referring to FIG. 2B, the available extruder barrel length is insufficient to perform all three steps, despite being run continuously in the same extruder. To this end, the extruder in which the third stage is carried out separately is schematically illustrated. The intermediate hard blend recovered in the second stage (in FIG. 2A) (blend B) is mixed with an additional third rubber (curable rubber 3) and a curing agent for the third rubber. In this particularly preferred embodiment, only two rubbers are used, a part of the curable rubber 2 has already been used in the first stage and the blend B is replaced with the remaining curable rubber 2 and further curing agent 2 to produce the final blend by dynamic vulcanization. As noted above, in other embodiments,
Blend B can be mixed with both curable rubbers 1 and 2, and additional curatives for rubbers 1 and 2. In yet another embodiment, Blend B is mixed with a curable rubber 3 and a curing agent 3 (for rubber 3) different from any of rubbers 1 and 2 as follows. Then a final blend with the desired properties is obtained.

Preferred curable rubbers are two or more of the following monomers, provided that at least one monomer has a functional group curable in the condensation reaction: alkyl acrylate, lower olefin, and functional group. Is an acrylate copolymer having

In the alkyl acrylate, the alkyl has 1 to 10 carbon atoms, typically 1 to 3 carbon atoms. Curable rubbers typically include a repeating unit having a functional group, and other repeating units selected from ethyl acrylate, butyl acrylate, ethylhexyl acrylate, and the like.

When selecting a repeating unit derived from an olefin, the olefin preferably has 2 to 6 carbon atoms. A typical curable rubber may include ethylene, propylene or butylene repeat units, and the molar ratio of such olefin units to acrylate repeat units is:
Typically it is less than 2, preferably in the range of 0.5 to 1.5.

Preferred functional groups for each of the two or more acrylic rubbers are selected from halogen, carboxyl, epoxy and hydroxy.

Suitable comonomers for pendant carboxylic acids include C _{2 to} C ₁₅ unsaturated acids, preferably those having 2 to 10 carbon atoms. An example of an acid functionalized acrylic rubber is DuPont's Vamac
And terpolymers of ethylene-acrylate-carboxylic acids such as G, and, inter alia, various carboxyl-functionalized acrylates sold by Zeon Corporation.
In the condensation reaction, the proportion (weight) of the rubber having a repeating unit having a curable functional group is less than about 10 mol%, and preferably about 0.5 to 4% by weight, based on the weight of all the repeating units. It is.

Suitable comonomers for the pendant epoxy group include unsaturated oxiranes such as oxirane acrylate, where the oxirane group has 3 to about 10 carbon atoms and the ester group of the acrylate has 1 to 10 carbon atoms. A particular example of which is glycidyl acrylate. Another group of unsaturated oxiranes are various oxirane alkenyl ethers, wherein the oxirane group has 3 to about 10 carbon atoms, the alkenyl group has 3 to about 10 carbon atoms, and specific examples are , Aryl glycidyl ether. Examples of epoxy-functionalized acrylic rubbers include, among others, Acrylate AR-53 and Acrylate AR-Nippon Zeon.
31.

Suitable comonomers for the hydroxy group contain C _{2 to} C ₂₀ unsaturated alcohols, preferably 2 to 10 carbon atoms. A specific example of a hydroxy-functionalized acrylic rubber is Nippon Zeon's Hytem.
p) 4404.

Preferred rubbers having functional groups are terpolymers of C _{2 to} C ₃ olefins, C _{1 to} C ₄ acrylates and acrylic or methacrylic acid. The olefin is present in a range from about 35 to 80 mole%, preferably about 45 to 55 mole%. Acrylate is about 10
To about 60 mol%, preferably about 37 to about 50 mol%
Exists in the range. The carboxylic acid is present in about 0.5 to about 10
Mol%, preferably in the range of about 2 to about 8 mol%. Typical commercially available terpolymers are Bamak G, Bamak LS, Bamak GLS, Bamak 6796, etc. manufactured by DuPont.

The curing of the rubber at each stage is acceptable in an amount sufficient to substantially completely cure the rubber, ie as low as about 80% for a lower degree of curing, but at least is acceptable. At 90%, it is done in the presence of one or more effective amounts of hardener. The degree of cure is easily measured from the amount of acrylic rubber not dissolved in toluene at 20 ° C. Suitable crosslinkers cure each rubber and provide covalent bonds between the reactive groups. It is preferred to use nitrogen-containing crosslinkers such as amines, and preferably two nitrogen-containing crosslinker compounds such as diamines. Examples of suitable crosslinking agents include various maleimides, various diisocyanates such as toluene diisocyanate, various isocyanate terminated polyester prepolymers, and various polyamines such as methylene dianiline. Additionally,
Various epoxides such as diglycidyl ethers such as bisphenol A may be used.

Highly preferred curing agents are Texaco
co) released by Jeffamin
e) Amine-terminated polyethers exemplified by the ED series of polymers. Another class of curing agents are diamine carbamates exemplified by hexamethylene diamine carbamate, such as Diak # 1 sold by DuPont.

The amount of effect agent used generally ranges from about 0.5 to about 12 parts by weight, preferably about 1 to 5 parts by weight, per 100 parts by weight of the particular rubber being vulcanized.

Optionally, in conjunction with a curing agent, to reduce the cure time of the two or more functionalized acrylic rubbers,
Accelerators may be used. Suitable accelerators include various fatty acid salts that do not crosslink with the functionalized rubber compound. Such compounds are often suitable as lubricants. Fatty acid salts generally have 12 or 14 to 20 or 25 carbon atoms. Suitable cations include alkali and alkaline earth metals, ie, Groups 1 and 2 of the Periodic Table, and various transition metals, eg, Groups 11 and 12 of the Periodic Table. Particular examples of accelerators are sodium, fatty acids such as palmitic acid, stearic acid, oleic acid, etc.
Salts of potassium, magnesium, calcium, zinc, etc.
And mixtures thereof, with potassium and magnesium stearate being preferred. The amount of accelerator used is low, from about 0.1 to about 4 or 5 parts by weight, most typically from about 0.5 to about 1.5 parts by weight per 100 parts by weight of the rubber being cured.

A preferred first rubber is a Bammacter polymer having a repeating unit having a carboxyl reaction cure site, and a preferred second rubber is an acrylic rubber having a chloroacetate reaction cure site. Thus, in the first step, a vulcanized rubber is produced in which only the carboxyl groups are cured and the chloroacetate groups are not.
The first stage blend has two Tg's, but with or without a single low brittle temperature (LTB) depends on the specific functional groups of each rubber and its relative amount.

In a second step, the addition of a hardener for the plastic and the second rubber forms a hard blend where the plastic is the continuous phase.

In the final stage, when more rubber to be cured and a curing agent for the rubber are added, the final blend formed is sufficiently dense and soft.

In the following illustrative examples, all “parts” mean “parts by weight”.

[0047]

Example 1 Rubber having a carboxyl group, especially about 50: 45: 5
VMAC-6796, a terpolymer of ethylene, methyl acrylate, and acrylic acid in a weight ratio of
Is blended with a rubber having the same amount of chloroacetate groups, especially Hightemp 4051CG, a copolymer of ethyl acrylate and lower alkyl, C ₁ -C ₄ vinyl chloroacetate, in a weight ratio of about 95: 5. The mixture is cured in a Banbury mixer, along with Diak # 1 (hexamethylenediaminecarbamate), a curing agent for Bamack, and an additional inert inorganic or organic filler, removing gases released during this time. To produce Blend A. Examples of inorganic fillers are sintered clay, titanium dioxide, silica, and talc. Examples of organic fillers are crushed peanuts, cashew nut shells,
Coconut charcoal, saturated fatty acids and fluorocarbon polymers.

67.5 parts of Blend A are mixed with 40 parts of Nylon 6 Ultramid B3 and a tertiary amine curing agent (ACM curing agent Hightemp SC-75), a lubricant, a processing aid, and an antioxidant Dynamic vulcanization in the presence of an oxidizing agent,
Pellet and dry in a dry hopper dryer at 230 ° F. for 4 hours to produce Hard Blend B.

Next, 50 parts of Blend B are mixed with 50 parts of Blend A, and a tertiary amine curing agent (ACM curing agent Hightemp SC-75), a lubricant / filler, a processing aid, and an antioxidant are added. Dynamic vulcanization in the presence of a twin screw extruder to produce soft blend C. Blend C
Produces a plastic / rubber ratio of 20/80, which gives surprisingly good oil swell and compression set properties to sufficiently dense pellets. The compression set given herein is based on compression formed plaque.

The components in Blend A and their relative amounts are shown below. Bamak VMR-6796 50 High Temp 4051CG 50 Bamak Hardener Dearc # 1 0.5 Inert Organic Filler 12 Total 112.5

The components in Blend B and their relative amounts are shown below. Blend A 112.5 Nylon 6, Ultramid B3 66.7 ACM curing agent, Hightemp SC-75 3.5 Inert organic filler 4 Naugard 445 2 Chemamide S221 2 Total 190.7

The properties of Blend B are shown below. Ultimate tensile strength (psi) 3113 (21.5 Mpa) Elongation at break (%) 125 100% modulus (psi) 3022 (20.8 MPa) Residual elongation (%) 66 Hardness (Shore A / D) 59D Oil swell (%) ) 125 ° C, 70 hours 1.4 Compression set (%) 150 ° C, 70 hours 96.5

The components in Blend C and their relative amounts are shown below. Blend A 112.5 Nylon 6, Ultramid B325 ACM curing agent, Hightemp SC-75 3.5 Inert organic filler 4 Nowgard 445 2 Chemamide S221 2 Santitizer 79TM 10 Total 159

The properties of Blend C are shown below. Ultimate tensile strength (psi) 1168 (8.1 Mpa) Elongation at break (%) 155 100% modulus (psi) 953 (6.6 MPa) Residual elongation (%) 26 Hardness (Shore A / D) 82A Oil swell (%) ) 125 ° C, 70 hours 4.6 Compression set (%) 150 ° C, 70 hours 83.3

Example 2 In a manner similar to Example 1 above, the same ingredients are blended into a final soft blend with similar relative amounts, ie, plastic: rubber = 20: 80. But,
Using a lower relative amount of the 30/70 polyamide / rubber mixture to form the intermediate hard blend in the second stage results in the formation of a softer intermediate hard blend, which is only slightly harder. This is the final blend, indicating that the remaining properties are substantially the same.

The components in Blend A and their relative amounts are shown below. Bamak VMR-6796 50 High Temp 4051CG 50 Bamak Hardener Dearc # 1 0.5 Inert Organic Filler 12 Total 112.5

The components in Blend B and their relative amounts are shown below. Blend A 112.5 Nylon 6, Ultramid B3 42.9 ACM hardener, Hightemp SC-75 3.5 Inert organic filler 4 Nowgard 445 2 Chemamide S221 2 Total 166.9

The properties of Blend B are shown below. Ultimate tensile strength (psi) 1962 (13.5 Mpa) Elongation at break (%) 140 100% modulus (psi) 1781 (12.3 MPa) Residual elongation (%)-Hardness (Shore A / D) 45D Oil swell (%) ) 125 ° C, 70 hours 5.3 Compression set (%) 150 ° C, 70 hours 91.5

The components in Blend C and their relative amounts are shown below. Blend A 112.5 Nylon 6, Ultramid B325 ACM curing agent, Hightemp SC-75 3.5 Inert organic filler 4 Nowgard 445 2 Chemamide S221 2 Santitizer 79TM 10 Total 159

The properties of Blend C are shown below. Ultimate tensile strength (psi) 1170 (8.1 Mpa) Elongation at break (%) 138 100% modulus (psi) 1010 (7.0 MPa) Residual elongation (%) 27 Hardness (Shore A / D) 85A Oil swell (%) ) 125 ° C, 70 hours 5.2 Compression set (%) 150 ° C, 70 hours 75.5

Example 3 In a manner similar to Example 1 above, the same rubber component is blended with the polyester to form a final soft blend.
Except that the plastic is polyester instead of nylon, the relative amounts of all components are maintained as described above.

The components in Blend A and their relative amounts are shown below. Bamak VMR-6796 50 High Temp 4051CG 50 Bamak Hardener Dearc # 1 0.5 Inert Organic Filler 12 Total 112.5

The components in Blend B and their relative amounts are shown below. Blend A 112.5 PBT, Cerenex 2002 66.7 ACM hardener, Hitemp SC-75 3.5 Inert organic filler 4 Nowgard 445 2 Chemamide S221 2 Total 190.7

The properties of Blend B are shown below. Ultimate tensile strength (psi) 985 (6.8 Mpa) Elongation at break (%) 73 100% modulus (psi)-Residual elongation (%)-Hardness (Shore A / D) 43D Oil swell (%) 125 ° C, 70 Time 7.1 Compression set (%) 150 ° C, 70 hours 79.7

The components in Blend C and their relative amounts are shown below. Blend A 112.5 PBT, SElenex 2002 25 ACM curing agent, Hightemp SC-75 3.5 Inert organic filler 4 Nowgard 445 2 Chemamide S221 2 Total 149

The properties of Blend C are shown below. Ultimate tensile strength (psi) 608 (4.2 Mpa) Elongation at break (%) 200 100% modulus (psi) 486 (3.4 MPa) Residual elongation (%) 12 Hardness (Shore A / D) 73A Oil swell (%) ) 125 ° C, 70 hours 9.5 Compression set (%) 150 ° C, 70 hours 53.9

Example 4 In a manner analogous to Example 3 above, the same ingredients are blended into a final soft blend with similar relative amounts, ie, plastic: rubber = 20: 80. But,
The use of a lower relative amount of 30/70 polyamide / rubber polyester to form the intermediate hard blend in the second stage results in a softer intermediate hard blend, which blends with the final softer blend. However, the remaining properties indicate that they are substantially the same.

The components in Blend A and their relative amounts are shown below. Bamak VMR-6796 50 High Temp 4051CG 50 Bamak Hardener Dearc # 1 0.5 Inert Organic Filler 12 Total 112.5

The components in Blend B and their relative amounts are shown below. Blend A 112.5 PBT, SElenex 2002 42.9 ACM hardener, Hitemp SC-75 3.5 Inert organic filler 4 Nowgard 445 2 Chemamide S221 2 Total 166.9

The properties of Blend B are shown below. Ultimate tensile strength (psi) 697 (4.8 Mpa) Elongation at break (%) 166 100% modulus (psi) 657 (4.5 MPa) Residual elongation (%) 15 Hardness (Shore A / D) 86A Oil swell (%) ) 125 ° C, 70 hours 11.6 Compression set (%) 150 ° C, 70 hours 70.8

The components in Blend C and their relative amounts are shown below. Blend A 112.5 PBT, SElenex 2002 25 ACM curing agent, Hightemp SC-75 3.5 Inert organic filler 4 Nowgard 445 2 Chemamide S221 2 Total 149

The properties of Blend C are shown below. Ultimate tensile strength (psi) 625 (4.3 Mpa) Elongation at break (%) 194 100% modulus (psi) 469 (3.2 MPa) Residual elongation (%) 10.3 Hardness (Shore A / D) 63A Oil swell (%) 125 ° C, 70 hours 11 Compression set (%) 150 ° C, 70 hours 69.6

Example 5 A blend made by the Horion two-step process:
Comparison with blends made by a three-step process

In the following two methods of producing two final blends of curable rubber and nylon, the same amount of each component is present in each final blend, and the blend of horions is produced in two steps ( (As shown in FIG. 1), the blend of the present invention is prepared in an additional third stage resulting from re-extrusion of the second stage intermediate hard blend where additional cured rubber condensate is added. Manufactured (as shown in FIGS. 2A and 2B)
Except for this, they are produced in extruders, each having suitable equipment.

In a manner similar to that described in Example 1, a copolymer of about 50 mole% ethylene, 45 mole% methyl acrylate, and about 5 mole% acrylic acid,
Bamaq GLS is replaced by High Temp 4051CG of the same weight.
(A copolymer of ethyl acrylate / vinyl chloroacetate in a weight ratio of about 95: 5). The mixture was cured in a Banbury mixer with Diarc # 1 and an inert organic filler, during which gas released was removed to produce Blend A.

Blend A was blended with Ultramid B3 nylon 6 in a two-stage Horion process by blending dynamically at a ratio of Blend A: Ultramid B3 = 4.5. Final blend). Blend A was also prepared in a three-stage process by using at least twice the amount of nylon 6 (Blend A: Ultramid B3 =
1.69) and no plasticizer, but in order to make the intermediate a sufficiently dense hard blend, blend B
(Intermediate hard blend).

The components of Blend H and Blend B are as follows. Blend H Blend B Blend A 112.5 112.5 Nylon 6, Ultramid B3 25 66.7 Hightemp SC-75 3.5 3.5 Inert Organic Filler 44 4 Nowgard 445 2-2 Chemamid S221 22 2 Santisizer 79TM 100 Total 159 199.7

Blend H is a tertiary amine curing agent (ACM)
It is dynamically vulcanized in a twin screw extruder in the presence of the curing agent Hightemp SC-75), a lubricant / filler, a processing aid, and an antioxidant, resulting in a plastic / rubber ratio of 20/80. The pellets of Blend B (formed in the second stage) are sufficiently dense and have a Shore D of greater than 40. When Blend H is pelletized for use in an injection molding machine, the pellets are spongy and wet, typically drying pellets of Blend B or C under ideal drying conditions. Requires about 5 to 10 times longer than required (see below).

In a manner similar to that described in Example 1, intermediate hard blend B was added with an additional amount of blend A
And vulcanized dynamically in a twin screw extruder in the presence of ACM hardener Hightemp SC-75, lubricants / fillers, processing aids and antioxidants, soft blend C
Generate Blend C produces a plastic / rubber ratio of 20/80, which results in sufficiently dense pellets.

The components in Blend C and their relative amounts are shown below. Blend A 112.5 Nylon 6, Ultramid B325 ACM curing agent, Hightemp SC-75 3.5 Inert organic filler 4 Nowgard 445 2 Chemamide S221 2 Santitizer 79TM 10 Total 159

The properties of Blend H and Blend C are shown below. Blend C Blend H Ultimate tensile strength (psi) 972 (6.7 Mpa) 856 (5.9 Mpa) Elongation at break (%) 184 248 100% modulus (psi) 682 (4.7 MPa) 595 (4.17 MPa) pellet Quality sufficiently dense Sponge-like hardness (Shore A) 76 61 Oil swell (%) 125 ° C, 70 hours 7 6.7 Compression set (%) 150 ° C, 70 hours 70 63

[Brief description of the drawings]

Detailed Description of the Drawings The foregoing and additional objects and advantages of the invention will be better understood by reference to the following detailed description, taken in conjunction with the prior art and schematic drawings of preferred embodiments of the invention.
The drawings are described below.

FIG. 1 is a schematic diagram of the prior art Horion, US Pat. No. 5,589,544, which is performed in two consecutive steps in an extruder where the final blend is recovered.

FIG. 2A is a schematic diagram of the process of the present invention, which is performed in two consecutive steps in an extruder where a sufficiently dense intermediate hard blend is recovered. FIG. 2B is a schematic of the third stage of the method of the present invention performed by re-extrusion of a fully dense intermediate hard blend containing additional curable rubber and curative for all uncured rubber. It is a figure.

 ──────────────────────────────────────────────────続 き Continued on the front page (71) Applicant 591162239 388 South Main Street, Akron, Ohio 44311-1059, United States of America of America (72) Inventor Craig Allen Kumirsky 44256, Ohio, United States of America Dina, countryside drive 994 F term (reference) 4F070 AA12 AA29 AA32 AA47 AA54 AB11 AB16 AC46 AE08 GA10 GB07 GB10 4J002 BG041 BG071 CD191 CF042 CF062 CF072 CF082 CF102 CH012 CL012 CL032 CL052 CL072 EN096 FD146

Claims (14)

[Claims] 1. A method for producing a vulcanized blend of an engineering thermoplastic (“plastic”) and at least two curable acrylic rubbers in a continuous step, comprising: 1) In the first stage, the first curable acrylic rubber is cured with the first curing agent in the presence of the second curable acrylic rubber that does not react with the first curing agent, and is simultaneously released Producing a first vulcanized rubber while removing gas, (2) in a second step, simultaneously removing gas released in the presence of the plastic and the first vulcanized rubber, Curing said second rubber with a second curing agent in a second condensation reaction to produce a sufficiently dense intermediate hard blend having a hardness of at least 40 Shore D; and (3) in a third step Curing additional curable rubber with additional curing agent in a continuous condensation reaction while simultaneously removing the evolved gas in the presence of said sufficiently dense intermediate hard blend, and having a Shore D of less than 30 Producing a final "soft" blend having a hardness of about 0.1% and being substantially free of plasticizer. 2. The amount of the plastic is sufficient to provide a continuous phase such that the vulcanized rubber is present as a dispersed phase, and the hardness of the intermediate hard blend is such that the second rubber is vulcanized. 2. The method of claim 1 wherein the method is controlled by the relative amounts of the second rubber and the plastic present when the second rubber is present. 3. In a third step, the additional curable rubber is a blend of the first and second curable rubbers and the additional curative is used for the first and second rubbers. The method of claim 1 comprising both curing agents. 4. In the third step, the additional curable rubber is the same as the second curable rubber,
The method of claim 1, wherein the additional hardener is the second hardener. 5. In a third step, the additional curable rubber is a third rubber different from the first curable rubber and the second curable rubber, and the additional curing agent is 2. The method of claim 1, wherein the method is for a third rubber. 6. The method of claim 2 wherein said second rubber in said first stage is a small percentage of the total weight of rubber in said final blend. 7. A vulcanized blend of an engineering thermoplastic (“plastic”) and first and second at least two curable acrylic rubbers, wherein: (1) in the first condensation reaction Curing the first curable acrylic rubber with the first curable agent in the presence of a second curable acrylic rubber that does not react with the first curing agent, while removing simultaneously released gas; Producing a first vulcanized rubber; (2) in a second condensation reaction, simultaneously removing the gas released in the presence of the plastic and the first vulcanized rubber, Is cured with a second curing agent to produce a sufficiently dense intermediate hard blend having a hardness of at least 40 Shore D; and (3) in a continuous condensation reaction, said sufficiently dense intermediate hard blend Cures additional curable rubber with additional curing agent while simultaneously removing the evolved gas in the presence of C, and has a hardness of less than 30 Shore D and is substantially free of plasticizer A vulcanized blend formed by producing a final "soft" blend. 8. The blend of claim 7 having a hardness ranging from about 30 Shore A to 30 Shore D. 9. The amount of the plastic is sufficient to provide a continuous phase such that the vulcanized rubber is present as a dispersed phase, and the hardness of the intermediate hard blend is such that the second rubber is vulcanized. 9. Control by the relative amount of said second rubber and said plastic present when performed.
Blend. 10. In the continuous condensation reaction (third stage), the additional curable rubber is a blend of the first and second curable rubbers and the additional curative is the second curable rubber. Including a curing agent for both the first and second rubbers,
A blend according to claim 8. 11. In the continuous condensation reaction (third stage), the additional curable rubber is the same as the second curable rubber and the additional curing agent is 9. The blend of claim 8, which is an agent. 12. In the continuous condensation reaction (third stage), the additional curable rubber is a third rubber different from the first curable rubber and the second curable rubber, 9. The blend of claim 8, wherein said additional hardener is for said third rubber. 13. The blend of claim 9, wherein said second rubber in said first stage is a small percentage of the total weight of rubber in said final blend. 14. The blend of claim 8 having a hardness ranging from 60 Shore A to 90 Shore A.