JP4131484B2 - Stepwise condensation, dynamic vulcanization process for producing substantially unplasticized plastic / rubber blends - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is a continuation-in-part of US patent application Ser. Nos. 08-686,782 and 08-686,798, filed Jul. 26, 1996.
[0002]
Polymer blends having a combination of elasticity and thermoplastic, referred to as “thermoplastic vulcanizates” or “TPVs” (formerly referred to as “thermoplastic elastomers” or “TPEs”), among others, have the desired hardness / softness. Manufactured by dynamic vulcanization to have temperature, oil and temperature resistance, oxidation resistance, and processability. In thermoplastic elastomers that are not physical blends, the properties depend 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, commonly referred to briefly as “plastic”. Most commonly, the plastic is selected from polyesters, polyamides, and polyolefins that provide a continuous phase of the hard phase in which dispersed regions of the “soft” phase of the elastomer are present. TPVs containing polyolefins are not the subject of the present invention, and the present invention relates to other “plastic” TPVs in combination with vulcanizable rubber (simply referred to herein as “curable”). Provides a relatively “soft” blend of controlled hardness (Shore D less than 30). Such blends are exceptionally resistant to oil swell and compression set.
[0003]
[Problems to be solved by the invention]
In markets that require blends of polar engineering thermoplastics that contain a dispersed “polar rubber” phase and a continuous “plastic” phase, the “rubber” phase is a major fraction of the “plastic” phase by weight. Present, the blend has a low oil swell and hardness in the range of Shore A30 to Shore D30. In particular, a blend having 60 to 90 Shore A is needed. Such “polar rubber / plastic” blends of polyamide and acrylic rubber, or polyester and acrylic rubber are too viscous to be produced in conventional equipment and are substantially plastic even if the actual blend is produced. It is not converted. That is, blends are not useful if they contain more than 30 parts by weight of plasticizer. “Not useful” means that the plasticizer oozes from the blend at the processing temperature, typically 250 ° C., and also at ambient temperature. Useful pellets must have a specific gravity in the range of 0.9 to 1.2 and are not porous (or sponge-like). This is confirmed by having a particularly high moisture content even when the pellets are dried over an extended period of time. In particular, blends with polyolefins can be heavily plasticized and have significant value. However, vulcanized blends of acrylic rubber with nylon, PBT, and a vast variety of other non-polyolefins do not reach the desired product unless they are substantially free of plasticizers or compatibilizers. “Substantially free” means that the blend has less than 30 parts by weight of plasticizer per 100 parts by weight of rubber. When curable acrylic rubber is present in the majority of weight (ie, “rubber rich”), the prior art methods produce undesirable, porous blends. Acrylic rubber, such as ethylene methyl acrylate copolymer, containing repeat units derived from monoolefinically unsaturated monomers that do not have a curable functional group (or reactive site) is used as a terminology herein. Not curable rubber. A sufficiently dense, but preferably soft, rubber-rich 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 strains and oil swell resistance). “Sufficiently dense” means that there is essentially no porosity measured. If pelletized, the specific gravity of the pellet is the same as the article molded from the pellet.
[0004]
[Prior art]
Polar blends are produced by dynamic vulcanization using condensation reactions with small molecule release, such as additional dynamic vulcanization with olefin rubber and polyolefin thermoplastics. In comparison, it is relatively slow. The condensation reaction has a detrimental effect on the physical properties of the blend at temperatures below a certain temperature and should be performed in the presence of sufficient plasticizer to promote the blending of the components below such temperatures. I can't. If the released small molecule is not processed, it is packed as a sponge-like mass in the blend. Accordingly, such blends are preferably produced in a substantially continuous process using a suitable exhaust system, which is operated at the required temperature in the range of about 200 ° C to 275 ° C, This is because it is impractical to fully seal a batch mixer such as Banbury to add components in stages and to remove reaction products. Also, the blends were prepared separately and in distinct stages using a relatively short mixed reaction zone, and were dynamically vulcanized at each stage before introducing the pellets to the next stage. It is generally very expensive to pelletize the blend.
[0005]
Different lengths of continuous mixers or mixing extruder barrels are available, but commercially available barrels have a ratio of length (L) to diameter (D) not exceeding 80. . They are typically in the range of about 20-80. Thus, for all practical purposes, a continuous process for producing blends must be completed in a barrel with an L / D not exceeding 80, with an L / D near 20 barrels. Where a method for removing small molecules released for a continuous condensation reaction is provided, the method can be carried out in two or more separation steps.
[0006]
Methods for making blends with non-polyolefinic “plastics” are taught in Horrion US Pat. No. 5,589,544 and 08-686,782 and 08-686,798 applications filed Jul. 26, 1996. ing. By “non-polyolefinic” plastic is meant that the plastic is substantially free of polyolefin chains. The term “plastic” refers to polyamide, polycarbonate, polyester, polysulfonate, Polylactone , Polyacetal, acrylonitrile-butadiene-styrene (ABS), polyphenylene oxide (PPO), polyphenylene sulfide (PPS), styrene-acrylonitrile (SAN), polyimide, styrene-maleic anhydride (SMA), and aromatic ketones Refers to the selected resin, any of which can be used alone or in combination with the other. The most preferred engineering resins are polyamide and polyester.
[0007]
In Holion US Pat. No. 5,589,554, in a first stage, a cured rubber concentrate (CRC) is prepared and in a second stage substantially blended with an engineering thermoplastic, optionally a compatibilizer. The CRC is formed from a mixture of a curable plastic acrylic copolymer ("rubber") and an acrylic "polymer carrier" that does not react with the curing agent for the rubber. Rubber is not miscible with the polymer carrier.
[0008]
Referring to FIG. 1, there is schematically shown an extruder mixing (discharge) barrel in which the two-stage process of US Pat. No. 5,589,554 is carried out continuously. Supplying a mixture of curable rubber 1 and curable rubber 2 (hereinafter “carrier”) to the first stage of the extruder, together with a curing agent for the 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 stage, the CRC is blended with plastic and, if necessary, additional additives and compatibilizers (column 8, lines 57-67). The carrier can be cross-linked during mixing with the plastic using a different curing agent than that used to cure the curable rubber (Column 9, lines 1-5). However, the plastic blend formed directly in the second stage (Blend H) tends to be porous, as described in Holion US Pat. No. 5,589,554. Porous (sponge-like) pellets of blend H are trapped in water in the pelletizing process and difficult to handle in the continuous processing process. It is not practical to dry such wet pellets before continuous processing. Using an extruder, if the blend is formed in the desired plastic to rubber ratio, the pellets that become unsuitable for injection molding will trap water in order to form a relatively soft TPV.
[0009]
No. 08-686798 filed a first curable acrylic rubber and curable terpolymer in the presence of a curing agent and plastic to form a blend having a single low temperature brittle temperature (LTB). A method of vulcanization is disclosed. The 08-686,782 application discloses a method of crosslinking at least a first and a second curable acrylic rubber (each having different functional groups) in a plastic substantially without the influence of a vulcanizing agent. . Curable rubbers are compatible with each other and with engineering plastics. “Compatible” means 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 rubber is C ₂ Thru C _Three C in combination with one or more groups selected from olefin, carboxyl, hydroxyl, epoxy, halogen, etc. ₁ Thru C _Ten Has an alkyl group.
[0010]
The intermediate hard blend is first made with the first curable acrylic resin, substantially without the use of a plasticizer, so that the final blend has less than 30 Shore D, preferably less than 90 Shore A. Uses a three-stage process that includes successive first and second condensation reactions to form and secondly form a second cured blend with other curable acrylic rubber within the intermediate hard blend The method of doing is not known. The first curable rubber contains different functional groups than the second curable rubber.
[0011]
As can be seen by the comparative illustration shown below, the blend of US Pat. No. 5,589,554 has components present in relative amounts similar to the blends produced by the three-step process of the present invention, but with Holion's Blends produced by the two-step process taught in US Pat. No. 5,589,554 have surprisingly different properties.
[0012]
[Means for Solving the Problems]
A composition comprising at least two curable rubbers blended with a polar engineering thermoplastic (simply referred to as “plastic”) as taught in the above-mentioned US Pat. Nos. 5,589,554 and 08-686798. It has been discovered that in a three stage process, including a body processing stage, it can be manufactured with sufficiently dense and controlled physical properties. The important intermediate step results in only the first curable rubber being cured to form a fully dense intermediate hard blend with Shore D greater than 40. The intermediate hard blend provides a microstructure that, in the third stage, can undergo further controlled improvements when the second curable rubber is cured.
[0013]
The three-stage method involves the plastic with first and second at least two polar acrylic rubbers each having a repeating unit derived from a monoolefinically unsaturated crosslinking monomer and each having a functional group curable by a different curing agent. Brought by blending. That is, each curing agent is effective for one functional group but not the other. Such repeating units of the crosslinking monomer are capable of crosslinking polymer chains comprising acrylate repeating units and, if present, repeating units of non-acrylate copolymerizable monomers. Each rubber is cured by a continuous condensation reaction that releases small molecules. It is therefore important that the small molecules released during rubber curing are simultaneously removed from the reaction zone.
[0014]
The three-stage process is required to be vulcanized step by step through successive condensation reactions, and in the first stage sufficient to produce a dynamically vulcanized blend in which rubber is present as the dispersed phase. It is required to use an amount of a second rubber. 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, where no plastic is present, the first condensation reaction occurs while the first curable rubber is blended with the second curable rubber, but the first curable rubber Only the rubber is cured with the first curing agent. Other blends having functional groups that are sensitive to the same first vulcanizing agent are also cured.
[0015]
Thus, in the second stage, in the presence of plastic, a second curable rubber present with the second curing agent, and, if present, functionalities susceptible to the same second curing agent. A second condensation reaction occurs by curing other rubbers having groups. Thus, the formed intermediate hard blend is sufficiently dense, has a Shore D hardness of at least less than 40, and can be as high as Shore D80.
[0016]
In a third stage, sufficient additional curable rubber (“third rubber”) and additional curing agent (“third curing agent”) to provide the desired essentially sufficiently dense final blend. , Preferably in combination with a first cured rubber and a second uncured rubber. The third rubber has functional groups but need not be essentially different from the functional groups of the first or second rubber. The functional group of the third rubber can be the same as or different from the first or second curable rubber functional group. If 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 can 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.
[0017]
Preferably, when the first and second curable rubbers are cured with the first and second curing agents, even if the process is operated step by step continuously in one long reaction zone, Even when operated in a differentiated process, an additional amount of the second curable rubber and its vulcanizing agent is optionally cured to produce the desired essentially sufficiently dense final blend. In combination with rubber, it is introduced in the third stage.
[0018]
It is preferred to carry out the blending in a reaction zone extending in the direction of the axis, but it is continuous if the reaction zone is long enough to simultaneously remove the released (small molecule) gas from the reaction zone. It can be performed in one pass or in two separate passes if the available reaction zone is relatively short to remove the gas released in each pass simultaneously. A typical reaction zone has an L / D ratio in the range of about 20 to about 80, and in the range of about 30 Shore A to about 30 Shore D, preferably 40 Shore A to 90 Shore A. A new final blend is produced that has a controlled hardness and is substantially free of plasticizers, typically process oils. The choice of L / D ratio and final blend components generally determines whether the method of forming the blend is a continuous or separate stage.
[0019]
More specifically, the three-stage vulcanized rubber is a first rubber first actuated with a first curative in the presence of an initial amount of a second rubber unaffected by the first curative. Prepared by condensation reaction. Preferably, the relative amounts of 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 vulcanizate. In the second stage, the second rubber is cured by the second curing agent in the presence of the plastic and releases a second small molecule in the second condensation reaction, with at least less than 40 Shore D, preferably Form a sufficiently dense intermediate hard blend with a Shore D of 40-80. Plastic is 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 (weight) of the first and second rubber to plastic is less than 5, 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 is cured in a further condensation reaction with an additional curing agent to produce the desired, final To produce a "soft" blend. Preferably, in the third stage, the ratio of additional rubber to plastic, 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.
[0020]
Most preferably, the first, second and third stages are performed sequentially in a mixing extruder long enough to facilitate the completion of all three stages to remove the final blend. The However, if restricted to an extruder of insufficient length for a continuous process, vulcanization recovers the first stage vulcanized rubber, preferably in the form of pellets, then in the second stage the pellets In the separation stage, the intermediate hard blend is fed with the plastic in an extruder to produce an intermediate hard blend, and in the third stage, the intermediate hard blend is blended with an additional amount of additional curable acrylic rubber and an additional anti-oxidant. 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 the rubbers are compatible with each other. It is preferable to select. It is most convenient to use an additional amount of the second rubber as an additional (third) rubber and use an additional amount of the second curing agent, preferably in combination with the cured first rubber. . Since it is desirable to maintain control of the continuous cure of the rubber, it is not desirable to use rubbers having functional groups that react with each other to self cure.
[0021]
Accordingly, a general object of the present invention is to provide a three-stage process for producing a substantially unplasticized vulcanized blend of plastic and first and second, at least two curable acrylic rubbers. In this method, (1) forming a first blend of a cured first rubber and an uncured second rubber, and then (2) a sufficiently dense intermediate A hard blend is formed and the hardness is the total amount of curable rubber present, i.e. the first and second in the mixture when the second rubber is vulcanized with the second curing agent in the second condensation reaction. Controlled by the amount of the second curable rubber and the curing agent, and then (3) different from the first and second rubber, or the same as either the first rubber or the second rubber, or these An additional curable rubber that is a blend of An additional curing agent that is different from or identical to the first and second curing agents is added to the intermediate hard blend and allowed to react in the third condensation reaction, or continuous with the second condensation reaction. To produce the final blend. The continuous condensation reaction is preferably carried out 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 amount of second rubber to the plastic and first curable rubber in the second stage and the reaction conditions. The final blend properties are finely tuned by the additional curable rubber in the third stage, the controlled addition of additional curatives, and the reaction conditions.
[0022]
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, the blend generally being less than 30 Having a hardness of less than 10 as measured by ASTM test D-471, having a resistance to compression set of at least 85 after 70 hours at 150 ° C., It is a specific object of the present invention to provide a process for making blends that is substantially free of plasticizers or compatibilizers conventionally used to plasticize prior art blends.
[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. can be used, but those having a Tm in the range of 160 ° C. to about 280 ° C. are preferred, rather typically Used for forming or forming operations. Examples of suitable polyamides include nylon 6, polypropiolactam (nylon 3), polyenthiolactam (nylon 7), polycapryl lactam (nylon 8), polylactam such as polylauryl lactam (nylon 12), polyaminoundecanoic acid ( Nylon 11), amino acid homopolymers such as polypyrrolidinone (nylon 4), dicarboxylic acid and diamine copolyamides 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 the like, polyamides that are aromatic and partially aromatic, copolymers such as caprolactam and hexamethylene adipamide (nylon 6/66), or such as nylon 6/6, 6/6, 10 Terpolymers, copolymers such as polyether polyamides, and mixtures thereof. Additional examples of suitable polyamides described in Encyclopedia of Polymer Science and Technology (by Kirk & Othmer), 2nd edition, volume 11, pages 315 to 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. The polyamide generally has a number average molecular weight of about 10,000 to about 50,000, and desirably about 30,000 to about 40,000. The amount of polyamide in the blend is generally about 25 to about 100 parts by weight, desirably about 30 to about 90 parts by weight, and preferably about 35 to about 75 parts by weight per 100 parts by weight of total acrylic rubber.
[0024]
Suitable thermoplastic polyesters include various ester polymers such as polyesters, copolyesters or polycarbonates, their monofunctional epoxy end-modified derivatives, mixtures thereof, and the like. The various polyesters can be either aromatic or aliphatic or a combination thereof, and generally a diol such as a glycol having a total of 2 to 6 carbon atoms, and preferably from about 2 to about 4 carbon atoms, and Derived directly or indirectly by reaction of fatty acids having a total of 2 to 20 carbon atoms, and desirably about 3 to about 15 carbon atoms, or aromatic acids having a total of about 8 to about 15 carbon atoms. The In general, aromatic polyesters include polyethylene terephthalate, polybutylene terephthalate, polyethylene isophthalate, polynaphthalene terephthalate, as well as end-modified epoxy derivatives such as monofunctional epoxy polybutylene terephthalate. preferable. Various polycarbonates can be used, as are the esters of carboxylic acids. Suitable polycarbonates are those based on bisphenol A, ie poly (carbonyldioxy-1,4-phenyleneisopropylidene-1,4-phenylene).
[0025]
The various ester polymers also comprise at least one polyester and a polyether derived from a glycol having 2 to 6 carbon atoms, such as polyethylene glycol, or a polyalkylene derived from an alkylene oxide having 2 to 6 carbon atoms. Also included are block polyesters comprising at least one rubbery block such as ether. A preferred block polyester is polybutylene terephthalate-b-polyethylene glycol, such as Hytrel sold by DuPont.
[0026]
Preferably, rather than a plurality of plastics, for example, use only one generic class of plastics, such as polyamide or polyester, which is used in a small proportion to the total amount of rubber in the blend. . Preferably the plastic is in the range of about 10 to less than 50 parts, more preferably about 20 to 40 parts per 100 parts by weight of acrylic rubber. The presence of most of the plastic in the blend results in a blend with a hardness that is too high, i.e., Shore D higher than 30.
[0027]
Referring to FIG. 2A, an extruder is schematically described in which the first two steps are carried out continuously and continuously. In the first stage, the rubber masterbatch (Blend A) can be cured with less than the total amount (used) of the curable rubber 1 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 adjacent chain reaction sites of the same rubber. When using a plurality of first rubbers (referred to as such because they can be cured with the same first curing agent), the condensation reaction can be either or both (or all the plurality of first) rubbers. Progress with the chain.
[0028]
The one or more functionalized first and second acrylic rubbers are generally compatible with each other and are also compatible with the plastic, especially when it is a polyamide or polyester.
[0029]
In the second stage, a rubber masterbatch (Blend A) is blended with a selected plastic and cured with a second curing agent (curing agent 2). The second curing agent initiates a condensation reaction of the functional groups on the rubber with the reactive sites of adjacent chains of the same rubber, producing a sufficiently dense intermediate hard blend. When using a plurality of second rubbers that are cured with the same second curing agent, the condensation reaction proceeds with either or both (or all of the plurality of second) rubber chains.
[0030]
Referring to FIG. 2B, because the length of the available extruder barrel is insufficient to carry out all three steps, despite being carried out continuously in the same extruder. FIG. 2 schematically shows an extruder in which the third stage is carried out separately. The intermediate hard blend (blend B) recovered in the second stage (in FIG. 2A) 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 is already used in the first stage, and blend B is used for the rest of the 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 rubber 1 and rubber 2 curing agents. In yet another embodiment, blend B is mixed with a curable rubber 3 and a curing agent 3 (for rubber 3) different from either rubber 1 and 2 as follows. A final blend having the desired properties is then obtained.
[0031]
A preferred curable rubber is an acrylate having two or more of the following monomers: alkyl acrylate, lower olefin, and functional group, provided that at least one monomer has a functional group curable in the condensation reaction. A copolymer of
[0032]
In the alkyl acrylate, the alkyl has 1 to 10 carbon atoms, typically 1 to 3 carbon atoms. The curable rubber typically includes repeating units having functional groups and other repeating units selected from ethyl acrylate, butyl acrylate, ethyl hexyl acrylate, and the like.
[0033]
When selecting repeating units derived from olefins, the olefins preferably have 2 to 6 carbon atoms. Typical curable rubbers may contain ethylene, propylene or butylene repeat units, and the molar ratio of such olefin units to acrylate repeat units is typically less than 2, preferably 0.5 to 1.5. It is a range.
[0034]
Each preferred functional group of the two or more acrylic rubbers is selected from halogen, carboxyl, epoxy, hydroxy.
[0035]
Suitable comonomers for pendant carboxylic acids are C ₂ Thru C ₁₅ Of unsaturated acids, preferably those having 2 to 10 carbon atoms. Examples of acid functionalized acrylic rubbers include ethylene-acrylate-carboxylic acid terpolymers such as DuPont's Vamac G, and various carboxyl functionalized products, among others, available from Nippon Zeon. Contains acrylate. The proportion (by weight) of rubber having repeating units having curable functional groups in the condensation reaction is less than about 10 mole percent, and preferably about 0.5 to 4 weight percent, based on the weight of all repeating units. It is.
[0036]
Suitable comonomers for pendant epoxy groups include unsaturated oxiranes such as oxirane acrylates, the oxirane groups having from 3 to about 10 carbon atoms, and the acrylate ester groups being alkyls having from 1 to 10 carbon atoms. A specific example is glycidyl acrylate. Another group of unsaturated oxiranes are various oxirane alkenyl ethers, wherein the oxirane group has from 3 to about 10 carbon atoms, the alkenyl group has from 3 to about 10 carbon atoms, specific examples are , Aryl glycidyl ether. Examples of epoxy functionalized acrylic rubbers include, among others, Nippon Zeon's Acrylate AR-53 and Acrylate AR-31.
[0037]
Suitable comonomers for the hydroxy group are C ₂ Thru C ₂₀ Unsaturated alcohols, preferably containing 2 to 10 carbon atoms. A specific example of a hydroxy-functionalized acrylic rubber is Nippon Zeon's Hytemp 4404.
[0038]
Preferred rubbers having functional groups are C ₂ Thru C _Three Olefin, C ₁ Thru C _Four A terpolymer of acrylate and acrylic acid or methacrylic acid. The olefin is present in the range of about 35 to 80 mol%, preferably about 45 to 55 mol%. The acrylate is present in the range of about 10 to about 60 mole percent, preferably about 37 to about 50 mole percent. The carboxylic acid is present in the range of about 0.5 to about 10 mole percent, preferably about 2 to about 8 mole percent. Typical commercially available terpolymers are Bamak G, Bamak LS, Bamak GLS, Bamak 6796, etc., manufactured by DuPont.
[0039]
The cure of each stage of rubber is acceptable in amounts sufficient to substantially completely cure the rubber, ie, as low as about 80% for a lower degree of cure, but at least 90% In the presence of one or more effective amounts of curing agent. The degree of cure is easily measured from the amount of acrylic rubber not dissolved in toluene at 20 ° C. A suitable cross-linking agent cures each rubber to provide a covalent bond between the reactive groups. It is preferred to use a nitrogen-containing crosslinker such as an amine and preferably a crosslinker compound containing two nitrogens such as a diamine. Examples of suitable crosslinking agents include various maleimides, various diisocyanates such as toluene diisocyanate, various isocyanate-terminated polyester prepolymers, and various polyamines such as methylenedianiline. Additionally, various epoxides such as diglycidyl ethers such as bisphenol A can be used.
[0040]
Highly preferred curing agents are amine-terminated polyethers exemplified by the Jeffamine ED series of polymers sold by Texaco. Another class of curing agents are diamine carbamates exemplified by hexamethylene diamine carbamates such as Diak # 1 sold by DuPont.
[0041]
The amount of effect agent used is generally in the range of 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.
[0042]
Optionally, in connection with the curing agent, an accelerator may be used to reduce the curing time of two or more functionalized acrylic rubbers. 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 metals and alkaline earth metals, ie, Groups 1 and 2 of the periodic table, and various transition metals, such as Groups 11 and 12 of the periodic table. Specific examples of accelerators include salts of fatty acids such as palmitic acid, stearic acid, oleic acid, etc., such as sodium, potassium, magnesium, calcium, zinc, and mixtures thereof, potassium stearate and magnesium stearate Is preferred. The amount of accelerator used is small, from about 0.1 to about 4 or 5 parts by weight per 100 parts by weight of rubber to be cured, most typically from about 0.5 to about 1.5 parts by weight.
[0043]
A preferred first rubber is a bacmactor 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. Accordingly, in the first stage, a vulcanized rubber is produced in which only the carboxyl group is cured and the chloroacetate group is not cured. The first stage blend has two Tg, but whether or not it has a single low embrittlement temperature (LTB) depends on the specific functional groups of each rubber and their relative amounts.
[0044]
In the second stage, the hardener for the plastic and the second rubber is added to form a hard blend in which the plastic is a continuous phase.
[0045]
In the final stage, adding more rubber to be cured and a curing agent for that rubber, the final blend that is formed is sufficiently dense and soft.
[0046]
In the following illustrative examples, all “parts” mean “parts by weight”.
[0047]
【Example】
Example 1
Rubbers having carboxyl groups, in particular Bamac VMR-6796 which is a terpolymer of ethylene, methyl acrylate and acrylic acid in a weight ratio of about 50: 45: 5, and in particular rubbers having the same amount of chloroacetate groups, Ethyl acrylate and lower alkyl in a weight ratio of about 95: 5, C ₁ Thru C _Four High Temp 4051CG, which is a copolymer of vinyl chloroacetate, is blended. The mixture is cured in a Banbury mixer along with Diak # 1 (hexamethylenediamine carbamate), a hardener for bamac, and additional inert inorganic or organic fillers, removing any 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.
[0048]
67.5 parts of Blend A are mixed with 40 parts of Nylon 6 Ultramid B3 to provide tertiary amine curing agent (ACM curing agent Hightemp SC-75), lubricant, processing aid, and antioxidant. Dynamically vulcanize in the presence, pelletized, and dried in a dry hopper dryer at 230 ° F. for 4 hours to produce hard blend B.
[0049]
50 parts of Blend B is then mixed with 50 parts of Blend A in the presence of a tertiary amine curing agent (ACM curing agent Hightemp SC-75), lubricant / filler, processing aid, and antioxidant. And dynamically vulcanized in a twin screw extruder to produce soft blend C. Blend C yields a 20/80 plastic / rubber ratio, which gives surprisingly good oil swell and compression set properties to fully dense pellets. The compression set given herein is based on a compression formed plaque.
[0050]
The ingredients in blend A and their relative amounts are indicated below.
Bamak VMR-6796 50
Hightemp 4051CG 50
Bamak hardener Diarc # 1 0.5
Inert organic filler 12
Total 112.5
[0051]
The ingredients in blend B and their relative amounts are displayed 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
[0052]
The properties of Blend B are displayed 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
[0053]
The ingredients in Blend C and their relative amounts are displayed below.
Blend A 112.5
Nylon 6, Ultramid B3 25
ACM curing agent, Hightemp SC-75 3.5
Inert organic filler 4
Nowguard 445 2
Chemamide S221 2
Sanchitizer 79TM 10
Total 159
[0054]
The properties of Blend C are displayed 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
[0055]
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. However, using a lower relative amount with a 30/70 polyamide / rubber mixture to form an intermediate hard blend in the second stage results in a softer intermediate hard blend that is slightly harder Only the final blend, indicating that the remaining properties are substantially the same.
[0056]
The ingredients in blend A and their relative amounts are indicated below.
Bamak VMR-6796 50
Hightemp 4051CG 50
Bamak hardener Diarc # 1 0.5
Inert organic filler 12
Total 112.5
[0057]
The ingredients in blend B and their relative amounts are displayed below.
Blend A 112.5
Nylon 6, Ultramid B3 42.9
ACM curing agent, Hightemp SC-75 3.5
Inert organic filler 4
Nowguard 445 2
Chemamide S221 2
Total 166.9
[0058]
The properties of Blend B are displayed 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
[0059]
The ingredients in Blend C and their relative amounts are displayed below.
Blend A 112.5
Nylon 6, Ultramid B3 25
ACM curing agent, Hightemp SC-75 3.5
Inert organic filler 4
Nowguard 445 2
Chemamide S221 2
Sanchitizer 79TM 10
Total 159
[0060]
The properties of Blend C are displayed 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
[0061]
Example 3
In a manner similar to Example 1 above, the same rubber component is blended with the polyester to form the final soft blend. The relative amounts of all components as described above are maintained except that the plastic is polyester instead of nylon.
[0062]
The ingredients in blend A and their relative amounts are indicated below.
Bamak VMR-6796 50
Hightemp 4051CG 50
Bamak hardener Diarc # 1 0.5
Inert organic filler 12
Total 112.5
[0063]
The ingredients in blend B and their relative amounts are displayed below.
Blend A 112.5
PBT, Cerenex 2002 66.7
ACM curing agent, Hightemp SC-75 3.5
Inert organic filler 4
Nowguard 445 2
Chemamide S221 2
Total 190.7
[0064]
The properties of Blend B are displayed 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 hours 7.1
Compression set (%) 150 ° C., 70 hours 79.7
[0065]
The ingredients in Blend C and their relative amounts are displayed below.
Blend A 112.5
PBT, Selenex 2002 25
ACM curing agent, Hightemp SC-75 3.5
Inert organic filler 4
Nowguard 445 2
Chemamide S221 2
Total 149
[0066]
The properties of Blend C are displayed 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
[0067]
Example 4
In a manner similar to Example 3 above, the same ingredients are blended into a final soft blend with similar relative amounts, ie plastic: rubber = 20: 80. However, the use of a lower relative amount of 30/70 polyamide / rubber to form an intermediate hard blend in the second stage results in a softer intermediate hard blend, which is a softer final Although it is a blend, it indicates that the remaining properties are substantially the same.
[0068]
The ingredients in blend A and their relative amounts are indicated below.
Bamak VMR-6796 50
Hightemp 4051CG 50
Bamak hardener Diarc # 1 0.5
Inert organic filler 12
Total 112.5
[0069]
The ingredients in blend B and their relative amounts are displayed below.
Blend A 112.5
PBT, Selenex 2002 42.9
ACM curing agent, Hightemp SC-75 3.5
Inert organic filler 4
Nowguard 445 2
Chemamide S221 2
Total 166.9
[0070]
The properties of Blend B are displayed 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
[0071]
The ingredients in Blend C and their relative amounts are displayed below.
Blend A 112.5
PBT, Selenex 2002 25
ACM curing agent, Hightemp SC-75 3.5
Inert organic filler 4
Nowguard 445 2
Chemamide S221 2
Total 149
[0072]
The properties of Blend C are displayed 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
[0073]
Example 5
Comparison of Hollion's two-stage blend and three-stage blend
[0074]
In the following two methods of producing two curable rubber and nylon final blends, the same amount of each component is present in each final blend, and the holion blend is produced in two stages (see FIG. 1). As shown), the blends of the present invention are produced in an additional third stage resulting from re-extrusion of the second stage intermediate hard blend, to which additional cured rubber condensate is added. Except for (as shown in FIGS. 2A and 2B), each is produced in an extruder having suitable equipment.
[0075]
In a manner similar to that described in Example 1, Bamac GLS, a copolymer of about 50 mole% ethylene, 45 mole% methyl acrylate, and about 5 mole% acrylic acid, was added to the same weight of Hitemp 4051CG ( A blend of about 95: 5 weight ratio of ethyl acrylate / vinyl chloroacetate copolymer). The mixture was cured in a Banbury mixer with Diarc # 1 and inert organic filler, during which the gas released was removed to produce Blend A.
[0076]
Blend A is blend H (final blend expected to be produced) by dynamically blending Ultramid B3 nylon 6 with a ratio of Blend A: Ultramid B3 = 4.5 in a two-stage Holion process. ). Blend A also uses nylon 6 (blend A: Ultramid B3 ratio = 1.69) in an amount of more than twice the amount of blend A used in a three-stage process, with a plasticizer used. Instead, it is used to form Blend B (Intermediate Hard Blend) in order to make the intermediate a sufficiently dense hard blend.
[0077]
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 4 4
Nowguard 445 2 2
Chemamide S221 2 2
Sanchisizer 79TM 10 0
Total 159 190.7
[0078]
Blend H is dynamically vulcanized in a twin screw extruder in the presence of a tertiary amine hardener (ACM hardener Hightemp SC-75), lubricant / filler, processing aid, and antioxidant, Produces a plastic / rubber ratio of / 80. The blend B pellets (formed in the second stage) are sufficiently dense and have a Shore D greater than 40. When blend H is pelletized for use in an injection molding machine, the pellets are sponge-like and wet, typically drying the pellets of blend B or C under ideal drying conditions It takes about 5 to 10 times longer than the time required for (see below).
[0079]
In a manner similar to that described in Example 1, intermediate hard blend B is mixed with an additional amount of blend A and ACM hardener Hightemp SC-75, lubricant / filler, processing aids and antioxidants. In the presence of the agent, dynamic vulcanization is performed in a twin screw extruder to produce soft blend C. Blend C yields a 20/80 plastic / rubber ratio, which results in sufficiently dense pellets.
[0080]
The ingredients in Blend C and their relative amounts are displayed below.
Blend A 112.5
Nylon 6, Ultramid B3 25
ACM curing agent, Hightemp SC-75 3.5
Inert organic filler 4
Nowguard 445 2
Chemamide S221 2
Sanchitizer 79TM 10
Total 159
[0081]
The properties of Blend H and Blend C are displayed 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 Fully 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 prior art Horion US Pat. No. 5,589,544 performed in two stages in succession in an extruder where the final blend is recovered.
FIG. 2A is a schematic diagram of the process of the present invention carried out in two successive stages in an extruder in which a sufficiently dense intermediate hard blend is recovered. FIG. 2B is a schematic representation of the third stage of the method of the present invention carried out by reextrusion of a fully dense intermediate hard blend containing curing agents for all additional curable rubber and uncured rubber. It is a simple figure.

Claims (1)

Polyamide, polycarbonate, polyester, polysulfonate, polylactone , polyacetal, acrylonitrile-butadiene-styrene (ABS), polyphenylene oxide (PPO), polyphenylene sulfide (PPS), styrene-acrylonitrile (SAN), polyimide, styrene-maleic anhydride (SMA) and engineering thermoplastic resin ("plastic") consisting of only one or a combination of two or more resins selected from the group consisting of aromatic ketones, and first and second, at least two curable A vulcanized blend of acrylic rubber,
(1) The first curable acrylic rubber is cured with the first curing agent in the presence of the second curable acrylic rubber which is a first condensation reaction and does not react with the first curing agent. The second curable to the first curable acrylic rubber used in the first condensation reaction in the step of producing the first vulcanized rubber while simultaneously removing the released gas. The relative amount of acrylic rubber is in the range of 1: 2 to 2: 1,
(2) It is a second condensation reaction, and the second rubber is cured with a second curing agent while simultaneously removing the released gas in the presence of the plastic and the first vulcanized rubber. And producing a sufficiently dense intermediate hard blend having a hardness of at least 40 Shore D, wherein the weight ratio of the first vulcanized rubber and the second rubber to the plastic is from 1.5 And (3) in a condensation reaction that is continuous with the second condensation reaction, in the presence of the sufficiently dense intermediate hard blend, the released gas is simultaneously While removing, cure the additional curable rubber with an additional curing agent, having a Shore D hardness of less than 30 and a plasticizer of less than 30 parts by weight per 100 parts by weight of rubber, First, the second, and the second rubber and either the same, or the ratio of the different said additional rubber is greater than 2 and less than 5, to produce a final "soft" blends, by The vulcanized blend that is formed.

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