JPS582338A - Preparation of thermoplastic elastomer - Google Patents

Abstract

PURPOSE:To carry out the uniform and selective crosslinking of the rubber part of a granular composite composed of a monoolefinic copolymer rubber and a polyolefin resin, without deteriorating the polyolefin resin, by mixing the granular composite with a solution obtained by dissolving a crosslinking agent in a solvent which can be impregnated into said composite. CONSTITUTION:A granular composite composed of 10-90pts.wt. of a monoolefinic copolymer rubber such as EPM, EPDM, etc. and 90-10pts.wt. of a polyolefin resin is mixed with a solution obtained by dissolving 1pt.wt. of a crosslinking agent in 0.3-20pts.wt., preferably 5-15pts.wt. of a solvent (e.g. benzene, hexane, etc.) which can be impregnated into said granular composite, under the condition which does not cause the decomposition of the crosslinking agent. The crosslinking agent is impregnated selectively and uniformly into the rubber part by this procedure. The mixture is then heated to a temperature to cause the decomposition of the crosslinking agent thus effecting the crosslinking reaction. The solution of the crosslinking agent may be used by dispersing in water whose weight is smaller than that of the granular composite.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermoplastic elastomer in which the rubber component of a composition comprising a monoolefin polymer rubber and a polyolefin resin is partially crosslinked.

Thermoplastic elastomers have excellent rubber elasticity and can be made into molded products of any shape by the same molding methods as thermoplastic resins, such as extrusion molding and injection molding. As a rubber-like material, it has been attracting attention in fields such as automobile parts, home appliance parts, coverings, electric wire coverings, and miscellaneous goods.

Among them, polyolefin thermoplastic elastomers are different from those obtained by polymerizing hard segments and soft segments like other polystyrene-based, polyester-based, and polyurethane-based thermoplastic elastomers. For example, polypropylene) and monoolefin copolymer rubber as soft segments are melt-kneaded, and in some cases, the rubber is partially cross-linked during melt-kneading. It has been studied extensively in the past, and is being actively put into practical use in automobile parts, taking advantage of its relatively low cost, flexibility, excellent heat deformation resistance, and weather resistance.

In particular, partially crosslinked polyolefin thermoplastic elastomers have excellent heat deformation resistance, rubber elasticity, etc., and are expected to be the most promising materials for future polyolefin thermoplastic elastomers.

As a manufacturing method for obtaining a thermoplastic elastomer, a Banbury mixer, a kneader, etc. are usually used to produce a monoolefin copolymer rubber (e.g., ethylene-propylene-diene copolymer 11, EPDM). ), ethylene-propylene copolymer rubber (EPM)) and polypropylene are mechanically melt-kneaded, and a crosslinking agent is added at this time to cause partial crosslinking.

Methods for obtaining such thermoplastic elastomers are described, for example, in JP-A-48-26838 and JP-A-51-14.
No. 5553, JP-A-52-37953, JP-A-56-
Methods such as No. i45B57 are known. However, these methods do not give much consideration to the method of adding the crosslinking agent, and only a method of simply adding the crosslinking agent (direct addition method) is described. This direct addition method has poor workability during addition, and in the case of production using an extruder, the direct addition method has poor addition efficiency.In particular, the powdered crosslinking agent is difficult to mix with granular monoolefin copolymer rubber or crystalline polypropylene resin. It is difficult to obtain products with stable quality because it is easy to separate and the addition accuracy is poor. Furthermore, in production using an extruder, Banbury, etc., the temperature must be raised to around 200°C before the added crosslinking agent is sufficiently dispersed in the monoolefin copolymer rubber and crystalline polypropylene resin. There is a possibility that the crosslinking agent (organic peroxide) may be locally present at an extremely high concentration due to adhesion or scattering. If an impact is applied to the unevenly distributed crosslinking agent, or if foreign substances that promote decomposition, such as reducing agents such as amines, are mixed in, there is a risk of explosion or ignition. There have been many accidents, and there are safety issues.

On the other hand, JP-A No. 54-138.6 has a safety aspect,
A block masterbatch of the crosslinking agent is produced by adding and kneading the monoolefin copolymer rubber at a high concentration below the decomposition temperature of the crosslinking agent using a roll, Banbury mixer, kneader, etc., and using this, a Banbury mixer, A method for obtaining a partially crosslinked thermoplastic elastomer using a kneader or the like is described. However, this method has the following problem 1.

That is, in order to knead the crosslinking agent into the monoolefin copolymer rubber at a temperature below the decomposition temperature, it is necessary to plasticize the rubber.
On the other hand, since it is necessary to knead at a temperature at which the crosslinking agent does not decompose, a rubber with a high propylene content and low viscosity is used as the rubber, and it is also necessary to use a crosslinking agent with a high decomposition temperature. There are restrictions on both crosslinking agents. Further, in view of the method for making a masterbatch, it is desirable that the crosslinking agent used be in powder form, and liquid crosslinking agents are disadvantageous in terms of workability and precision in the amount added.

Since the obtained masterbatch is in the form of a lump, when producing a thermoplastic elastomer using this masterbatch, an extruder cannot be used, but a Banbury or kneader must be used. In this case, the crosslinking agent contained in the bulk masterbatch takes time to disperse when it is kneaded with the monoolefin copolymer rubber and crystalline polypropylene resin, and the crosslinking agent is not sufficiently dispersed. The crosslinking agent begins to decompose, creating localized areas with high crosslinking density.
There is a risk of over-density gel forming in the resulting thermoplastic elastomer. Overdense gel deteriorates the appearance and physical properties of products molded from thermoplastic elastomers, so in order to prevent the occurrence of such overdensity gel, it is necessary to include a crosslinking retarder in the crosslinking agent masterbatch. , Ethylene-propylene-diene copolymer rubber with high ethylene content (E P
When using DM), it is difficult to completely suppress the occurrence of hyperdense gel.

Another method for blending a crosslinking agent into rubber is a solution blending method. That is, the rubber and crosslinking agent are dissolved in a good solvent, blended, and the resulting solution is reprecipitated. This method requires a large amount of organic solvent, and although it is possible in the laboratory, it is not suitable for industrial production.

On the other hand, a method is known in which the granular polyolefin resin is crosslinked by impregnating the granular polyolefin resin with a crosslinking agent such as an organic peroxide under heat in an aqueous medium (Japanese Patent Publication No.
No. 39264, JP-A-47-34436, JP-A-48
-43026). These are intended for crosslinking and foaming of polyolefin resins, and since polyolefin resins generally have high crystallinity, they are impregnated below the melting point of the polyolefin resin, and in crosslinking, the degree of impregnation of the crosslinking agent between the crystalline and non-crystalline parts of the polyolefin resin is reduced. Also, the degree of crosslinking becomes uneven, making it impossible to obtain a homogeneous crosslinked product. Therefore, it is necessary to raise the impregnation temperature to about the melting point of the polyolefin resin, and therefore, in order to prevent the polyolefin resin particles from fusing with each other, an anti-fusing agent such as basic zinc carbonate or tricalcium phosphate is required. do.

There is a method of mixing a crosslinking agent with a polyolefin resin, the so-called "mabashi mixing method", for example, as described in JP-A-53-5
No. 4247'1 describes a method in which a polyolefin resin and a crosslinking agent are directly mechanically mixed, and at that time, the crosslinking agent is melted by frictional heat and impregnated and adhered to the granular polyolefin resin.

Also in this case, the impregnation and attachment of the crosslinking agent to the polyolefin resin is limited to the surface and surface layer of the particles.

However, the present inventors have discovered that when monoolefin copolymer rubber is impregnated with a crosslinking agent in an aqueous medium, such problems do not arise and the crosslinking agent can be uniformly impregnated in an accurate amount. Headed to, JP-A-55-1307
No. 46, and when a monoolefin copolymer rubber and a crystalline polyolefin resin coexist in an aqueous medium, the crosslinking agent is selectively impregnated into the copolymer rubber. The same holds true even for a compound obtained by kneading a monoolefin copolymer rubber and a crystalline polyolefin resin, and a patent application filed in 1983 claims that granules in which the crosslinking agent is uniformly impregnated into the rubber component can be obtained. -172959.

Furthermore, the present inventors have developed these technologies, and in Japanese Patent Application No. 172960/1987, a granular composite consisting of a monoolefin copolymer rubber and a polyolefin resin is subjected to crosslinking in an aqueous medium in the required amount. The desired crosslinking is achieved by impregnating the particulate composite with the crosslinking agent under conditions that do not substantially cause decomposition of the crosslinking agent, and then raising the temperature to a temperature at which the crosslinking agent decomposes to partially crosslink the particulate composite. We have proposed a method for producing a granular partially crosslinked thermoplastic elastomer that is uniformly crosslinked at a temperature and is not degraded by kneading.

The inventors further investigated these technologies,
8- We succeeded in streamlining the process and improving productivity while maintaining the excellent features of the technology of Japanese Patent Application No. 54-172960.

That is, in the present invention, a granular composite consisting of a monoolefin copolymer rubber and a polyolefin resin is impregnated with a required amount of a crosslinking agent under conditions in which the crosslinking agent is not substantially decomposed, and then the crosslinking agent is In a method for producing a thermoplastic elastomer by partially crosslinking a granular composite by raising the temperature to a temperature at which decomposition occurs, the granular composite is impregnated in an amount of 0.3 to 20 parts by weight per 1 part by weight of a crosslinking agent. A solution in which a crosslinking agent is dissolved in a suitable solvent is mixed with the granular composite, either as it is or suspended in water with an equal weight or less than that of the granular composite.
This method of producing a thermoplastic elastomer is characterized in that after uniformly impregnating a crosslinking agent, a mixed system is heated to carry out a crosslinking reaction.

That is, the method of the present invention has high operational safety because the crosslinking agent, which is an organic peroxide, is not directly introduced into the high-temperature system.
Adding a crosslinking agent by impregnation allows you to accurately control the amount added, so products of the desired quality can always be produced stably, and the impregnation of the crosslinking agent is carried out selectively and uniformly in the rubber part. Even with static crosslinking, the crosslinking acts uniformly on the rubber, and even in the case of ethylene-propylene-diene copolymer rubber with a high propylene content, which has strong crosslinking properties, the generation of overdensified gel is prevented. Since the crosslinking agent is selectively impregnated into the rubber part, in addition to the existing feature of extremely little deterioration of polypropylene, which is easily susceptible to deterioration during crosslinking, the amount of water used is less than the weight of the granular composite.
In some cases, even when no aqueous medium is used at all, a thermoplastic elastomer that is well partially crosslinked can be obtained, which has various advantages.

That is, in the prior art, since the particulate composite is impregnated with the crosslinking agent in a suspended state in an aqueous medium, the amount of water used must be at least sufficient to suspend the particulate composite, and In order to maintain a uniform suspension state, a fairly vigorous stirring state is required, which causes problems such as deformation and damage of the granular composite due to the stirring blades, and limits on the ability to treat large amounts of water and improve productivity per treatment tank. Ta.

In contrast, the method of the present invention uses less water and
In some cases, the system does not contain any water at all, so the contact between the granular composite and the crosslinking agent can be made by simple mixing, so mild stirring is sufficient, causing less deformation and damage to the granular material, and improving productivity per treatment tank. expensive.

Furthermore, the dehydration work is shortened, and depending on the processing tank, dehydration and drying can be performed in the same tank, eliminating the need to separately prepare a centrifuge, dryer, etc.

In particular, when performing the impregnation of the present invention in a water-free system, hydrophobic monomers such as water-reactive monomers and water-soluble monomers, which could not be introduced in the presence of water, are simultaneously introduced. It is also possible to obtain partially crosslinked thermoplastic elastomers that can be impregnated and have unprecedented functionality.

Since the mixing and impregnation of the crosslinking agent in the present invention requires only mild mixing and stirring as described above, the reactor used in the present invention is a mixer type reactor in which the contents are mixed and stirred by shifting or shaking the reaction vessel. things are used. In particular, a type in which the reaction vessel rotates on its own axis by a rotating shaft is preferred, and the rotating shaft is preferably at an angle of 80° or less with respect to the horizontal axis. A reactor with a horizontal axis of rotation is generally used and is suitable as a reactor for the present invention. As such a reactor, a double cone type mixer, a type mixer, and a cylindrical type mixer, which are generally used as a rotating solid mixer, can be used, and a ribbon type mixer with an internal spiral ribbon blade can be used. can also be used.

Monoolefin copolymer rubber The monoolefin copolymer rubber used in the present invention can be made by polymerizing two or more monoolefins or further using a Ziegler-Natsuta catalyst consisting of a combination of a vanadium compound and an aluminum compound, for example. It is an essentially amorphous random copolymer copolymerized with at least one type of polyene. Typically, one of the monoolefins is ethylene and the other is propylene, but
Other monoolefins (general formula OH2:0HR) can also be used. The monoolefin copolymer rubber may be a saturated compound such as ethylene-propylene binary copolymer rubber (EPM), but the copolymer also contains at least one copolymerizable polyene. Ethylene-propylene-diene copolymer rubber (EPDM), which is a copolymer with unsaturation properties, may also be used. Usually, as the polyene, 1.4 hexadiene, dicyclopentadiene, methylenenorbornene, ethylidenenorbornene, propenylnorbornene, cyclooctadiene, methyltetrahydroindene, etc. are used.

Polyolefin resin The polyolefin resin used in the present invention is ethylene,
High molecular weight substantially crystalline solid obtained by polymerizing olefins such as propylene, butene-1, pentene-1,4-methylpentene-1, hexene-1, etc., alone or in copolymerization form, by a conventional method. It is a resinous thermoplastic. Therefore, crystalline polyolefins such as polyethylene (low, medium, or high density) are used.

Polypropylene is a preferred polyolefin resin;
Isotactic and syndiotactic propylene homopolymers with a high degree of crystallinity, propylene-ethylene block or random copolymers, propylene-butene-1 block or random copolymers, propylene-butene-1 block or random copolymers, triblock or random copolymer of ethylene, propylene/hexene-1
Block or random copolymer, propylene/hexenate ethylene triblock or random copolymer, propylene/4-methylpentene-1 block or random copolymer, propylene/4-methylpentene-ethylene triblock or random It includes crystalline copolymers of linear or branched α-olefins such as copolymers. Among these, propylene homopolymers, propylene/ethylene copolymers, and propylene/ethylene/hexene-1 copolymers are particularly preferred.

Composite ratio The composite ratio of the monoolefin copolymer rubber and polyolefin resin in the present invention is 10 to 90 parts by weight of the monoolefin copolymer rubber and 90 to 10 parts by weight of the polyolefin resin.

When the amount of monoolefin copolymer rubber is 10 parts by weight or less, the amount of crosslinked rubber is small, the advantage of partial crosslinking is lost, and quantitative introduction of the crosslinking agent becomes difficult, which is not preferable.

Furthermore, when the monoolefin copolymer rubber is 90 parts by weight or more, there are restrictions such as the need to select a relatively hard material with a high ethylene content in the case of EPM or EPDM, in order to obtain the composite in granular form. In addition, it is undesirable, has poor moldability, and has low utility value as a thermoplastic elastomer.

Composite method As a composite method for monoolefin copolymer rubber/polyolefin resin composite, each component is homogeneously kneaded using a normal melt kneading method, that is, a screw extruder, twin screw extruder, roll, Banbury mixer, etc. It is also possible to remove the granules (pellets).

In the method of the present invention, the monoolefin copolymer rubber/polyolefin resin composite is suspended and dispersed in an aqueous medium in the form of particles. The size of the particles may be as follows: 15 - The pellets supplied with the monoolefin copolymer rubber/polyolefin resin composite may be 1 to 7 mm
Preferably, the shape may be angular, cylindrical, or spherical, each having a diameter of about 2 to 5 mm.

Crosslinking Agent The crosslinking agent used in the present invention is impregnated into the monoolefin copolymer rubber/polyolefin resin composite particles in an aqueous medium without substantial decomposition thereof. Therefore, this crosslinking agent must be capable of being impregnated into the monoolefin copolymer rubber/polyolefin resin composite.

The crosslinking agent used in the present invention is oil-soluble and is an aromatic or aliphatic organic peroxide or an aso compound. The crosslinking agent is used by being dissolved in a solvent capable of impregnating the monoolefin copolymer rubber/polyolefin resin composite. Any solvent can be used as long as it can dissolve the plasticizer and impregnate the monoolefin copolymer rubber, and can be removed by volatilization in the drying process after impregnation. Aromatic solvents such as general nihabenzene, toluene, etc.
- aliphatic, such as heptane, heptane, cyclohexane, etc., 1% m
agent is used. The amount of the solvent used is 0.3 to 20 times, preferably 5 to 15 times, and usually about 10 times the weight of the crosslinking agent used. If it is less than 0.3 times, the amount of solvent is too small and uniform impregnation is not possible, and the crosslinking agent may adhere to the surface and may not work as a crosslinking agent. On the other hand, if it exceeds 20 times, it will not swell. I like it,
This is not preferable because the pellet surface may be melted by the solvent and the pellets may be fused together. By using this solvent, the crosslinking agent is diluted, thoroughly and uniformly mixed with the particulate composite, and uniform impregnation of the crosslinking agent is effected along with the impregnation of the solvent. Even when an aqueous medium is used for impregnation, the solvent is effective for uniform dispersion and impregnation of the crosslinking agent.

Note that it is also possible to use a commercially available crosslinking agent that has already been diluted with a solvent or the like.

There is no particular restriction on the half-life temperature of the crosslinking agent used in the present invention, but a humidity level that does not allow the granular composite to fuse in the impregnation crosslinking process is adopted, and in consideration of crosslinking reactivity (productivity), ]
It is desirable that the 0-hour half-life temperature is 60 to 90°C.

Crosslinking agents that can be used include octanoyl peroxide, lauroyl peroxide, benzoyl peroxide, p-chlorobenzoyl peroxide, 2,4-
Dichlorobenzoyl peroxide, cyclohexanone peroxide, t-butyl peroxybenzoate,
t-Butyl peroxyoctoate, methyl ethyl ketone peroxide, dicumyl peroxide, di-t-
Butyl peroxide, z, 5-dimethyl-2゜5-di(benzoylperoxy)hexane, 2゜5-dimethyl-2,5-di(t-butylperoxy)hexane, di-
t-Butyl-di-peroxyphthalate, t-butylcumyl peroxide, diisopropylbenzene hydroperoxide, 1,3-bis-(1-butylperoxyisopropyl)benzene, t-butyl peroxybeverley: 1) , 3,5.5-trimethylhexanoyl peroxide, 1.1-bis-(t-butylperoxy) 3,5.
5-trimethylcyclohexane, 111-bis=(1-
organic peroxides such as butylperoxy)cyclohexane,
There are other azo compounds such as azobisisobutyronitrile, etc., which may be used alone or in combination.

The amount of the crosslinking agent is about 0.1 to 10 parts by weight, preferably about 0.2 to 3 parts by weight, based on 100 parts by weight of the monoolefin copolymer rubber in the monoolefin copolymer rubber/polyolefin resin composite. The amount of crosslinking agent depends on the type of crosslinking agent, the type of monoolefin copolymer rubber, the compounding ratio, and the desired degree of crosslinking of the resulting partially crosslinked thermoplastic elastomer (23°C in cyclohexane for 48 hours, sample It is preferable that the gel fraction is in the range of 30 to 97% by weight when 0.25g of the gel is immersed and the remaining insoluble matter is measured as the gel fraction through an 80-mesh wire gauze.

Impregnation method □ The method of impregnating the crosslinking agent 19- into the granular composite composed of monoolefin copolymer rubber and polyolefin resin according to the present invention is to add the granular composite and a solvent to a mixer-type reactor as described above. This is carried out by adding a crosslinking agent dissolved in water or a dispersion of the crosslinking agent in water, and mixing and stirring. In this case, the amount of water used is equal to or less than the weight of the granular composite, preferably 1/2 or less. This is because when the amount of water is large, it becomes necessary to suspend the granular composite in an aqueous medium for uniform impregnation, and vigorous stirring using a stirring blade is required instead of the mixer type of the present invention. .

The impregnation operation is carried out at a humidity sufficiently lower than the decomposition temperature of the crosslinking agent used (usually room temperature to 10%
0°C). Although the pressure is normal pressure to 20 to 9/Crl, it is usually carried out around normal pressure.

In this impregnation operation, in order to uniformly impregnate the target rubber part, it is desirable to sufficiently impregnate the free crosslinking agent so that the amount of free crosslinking agent is 5% by weight or less of the amount of crosslinking agent used, and the impregnation time is usually 0. It takes 5 to 10 hours.

When using an aqueous dispersion for impregnating the crosslinking agent, 20
- Although a uniform dispersion system can be obtained by mixing and stirring in a reactor, dispersion can be made more easily and more stably by using an appropriate stabilizer.

As suspension stabilizers in this case, those commonly used as suspension stabilizers in aqueous suspension polymerization of vinyl monomers can be used, such as polyvinyl alcohol, polyvinylpyrrolidone, methylcellulose, hydroxycellulose, etc. water-soluble polymeric substances, anionic surfactants such as alkylbenzene sulfonates, nonionic surfactants such as polyoxyethylene alkyl ethers, or water-insoluble inorganic salts such as magnesium oxide and calcium phosphate alone, or Mix and add 0.0% to water. O1
It is used in an amount of about 10% by weight.

When impregnating a crosslinking agent into the granular composite consisting of monoolefin copolymer rubber and polyolefin resin as described above, plasticizers, lubricants, ultraviolet stabilizers, antioxidants, blowing agents, and crosslinking agents may be added as necessary. Auxiliary materials such as accelerators and crosslinking reaction retarders can be added and impregnated at the same time.

In addition, during this impregnation and mixing, a polymerizable monomer can be added to the crosslinking agent solution for impregnation in order to modify the granular composite. In particular, when water is not used for impregnation, a water-reactive monomer or It is possible to simultaneously impregnate hydrophobic monomers, such as water-soluble monomers, which have hitherto been unable to be introduced in the presence of water.

Crosslinking method Impregnation operation (Temperature° Normally, room temperature to 100°C1 Impregnation time =
0.5 to 10 hours), the temperature is raised to about 50 to 150°C, stirred for 2 to 10 hours, and then a crosslinking reaction is carried out to form a partially crosslinked thermoplastic. Elastomeric berets can be obtained.

After crosslinking, post-treatments such as pickling, water-washing, and drying are carried out as necessary, similar to the post-treatments of ordinary aqueous suspension polymerization of vinyl monomers. These post-treatments can be carried out in the same reactor without transferring the product.

The thermoplastic elastomer obtained by the present invention is used for various electric wire coatings (insulation, sheath), household appliance parts, automobile parts, and other industrial parts by methods such as extrusion molding, blow molding, and injection molding.

Specific uses include gaskets, flexible tubes,
These include hose coverings, weather stripping, flexible bumpers, side bumpers, moldings, filler panels, lamp housings, wire cable coverings, and air intake inlets.

Next, the present invention will be explained more specifically by examples.
The present invention is not limited to the following examples unless it exceeds the gist thereof.

During the experiment below, the test methods used to display the physical properties of each component and evaluate the resulting composition are as follows. However, 4)～(wa)
All measurement samples for item A were punched out from injection molded sheets with a thickness of 2 mm.

(1) Metsu gzu low-ray self-MFR) (230°cjAS
TM-D-1238 (g/10 minutes) (2) A-=One temperature CM"L"' 100℃), T
15-K-6300 (3) Gel fraction 0, 25 g of sample was immersed in 100 ml cyclohexane, left at 23-23°C for 148 hours, passed through an 80-mesh wire mesh, and the remaining insoluble matter [wt%] (4) Hardness (J Work 5-A) J Work S-ni-6301 (5) Tensile strength (breaking point) J Work S-ni-6301 No. 3 dumbbell [kg/C7+! ] (6) Tensile elongation (breaking point) J-Ko S-ni-6301 No. 3 dumbbell [%] (7) Heating and pressing deformation rate Apply a load to the sample in heated silicone oil and measure the deformation of the sample A sample (1 cm
Attach a sheet of 1mm x 2mm thick and apply a load of 3mm to the 1α x 1mm surface at temperatures of 130°C and 150°C.
After standing for a period of time, the load is removed and the thickness is deformed after 10 minutes. [%] (8) Put the sample into a cylinder with a diameter of 10 mm in a Q value enhancement type flow tester, heat it to 200 °C, and then
- a diameter of 1 m provided at the bottom of the cylinder with a load of
It is obtained by the amount of resin per second flowing out of an orifice with a length of m % of 2 mtn. (XI O= cc/sec
) (9) Preheating with a hyperdensity gel hydraulic press molding machine = 180°C% for 5 minutes, heating press = 180°C, 5 minutes, 150 kg /
c++1 cooling press: 30℃, 1 minute, 150k
Obtained under the condition of g/cr/1, thickness 1 mm, 200
If there is even one opaque foreign substance (overdense gel) in the mm x 200 mm press sheet, it is determined that it is present.

(10) Injection moldability Injection molding machine and compatible conditions: 5oz inline screw type mold: lQO+r+mXmX100mmX2 thick sheet injection pressure Crab? 5 kg/cn! Injection humidity: 230℃ Mold temperature: When injection molding is performed under conditions of 40℃ or higher, l OOmm
Injection moldability was judged to be good if it was possible to mold a sheet with a thickness of 1 x loom x 2, there was no delamination or deformation, and there was no 70-mark that significantly deteriorated the appearance.

Hygiene of α (dissolution test: potassium permanganate consumption substance) Wash the sample thoroughly with water, 2 ml per surface area ICd of the sample
Using a leaching solution (water) at a ratio of 3 and keeping at 95°C.
The solution left for 0 minutes is the test solution.

100ml of water in an Erlenmeyer flask. diluted sulfuric acid (1+3)5
m+z and 0.0IN hydrium permanganate solution 5m
Add t and boil for 5 minutes, then discard the liquid and wash with water. Take 100 ml of the test solution in this Erlenmeyer flask, add 5 mt of diluted sulfuric acid (1→3), and further add 10 mt of 0.0 IN hydrium permanganate solution, heat and boil for 5 minutes. Next, the heating was stopped, and 10 ml of 0.0 IN sodium oxalate solution was immediately added to decolorize the solution.
．． Titrate with 0IN potassium permanganate solution until a pink color remains.

Separately, conduct a blank test using the same method and calculate the amount of potassium permanganate consumed using the following formula.

However, a: Titration amount of 0.0IN potassium permanganate solution in this test (ml) Titration amount of O, OIN potassium permanganate solution in blF test (ml) Example 1 Autorotating reactor with internal capacity of 16 short tons 1,750 g of pure water was added to the tank, and ethylene/propylene/non-conjugated diene terpolymer rubber was added as a monoolefin copolymer rubber (
Propylene content M28%, Mooney viscosity 88, ethylidene norbornene as non-conjugated diene, iodine number 15
, hereinafter referred to as EP-1) and 60 parts by weight of polypropylene (MFR5g/l0) as a polyolefin resin.
5,240 g of pellets (hereinafter referred to as PP-1) were kneaded in a single-screw extruder and suspended by rotating the reactor.

As a crosslinking agent, 39.3 g of benzoyl peroxide (1.25 parts by weight per 100 parts by weight of monoolefin copolymer rubber) was dissolved in 393 g of benzene, and this was added to the suspension system. The 10 hour half-life temperature of this crosslinker is 74°C. After replacing the inside of the reactor with nitrogen gas, rotate the reactor (1
0 to l2r,p,,m), the temperature inside the system was raised to 60°C while thoroughly mixing the system, and rotational mixing was carried out at this temperature for 3 hours, followed by impregnation.

Next, in this state, the temperature was raised to 90'C and 5
After continuing to rotate and mix for a period of time to perform a static crosslinking reaction, use the filtration device attached to the bottom of the reactor to reduce the pressure inside the reactor to remove the suspension, and then further clean the system. Vacuum was applied, the pellets were dried, and the system was cooled to yield partially crosslinked thermoplastic elastomer pellets. This product was further passed through a single-screw extruder and then subjected to the following evaluations.

In this example, the weight ratio of granular composite/water was 3/1, and the total amount charged was about 60% of the reactor.

Gel fraction 78 [wt%] Hardness J5
-A98 Tensile strength 125 (kg/cJ) 28
- Tensile elongation 550 [%] Heating and pressing deformation rate ] 330°C1, g (%) 1506
C5,2 [%] Q value 2,2 (x1ci″” cc
/5ec) No over-density gel Injection moldability Good permanganese acid power consumption substance o, os (p
, p, m) Example 2 60 parts by weight of EP-1 as monoolefin copolymer rubber and 40 parts by weight of PP-1 as polypropylene were placed in a rotary reactor with a content of 16% t using a single-screw extruder. 5,760 g of pellets (obtained by kneading) were added.

As a crosslinking agent, 43.2 g of benzoyl peroxide (1.25 parts by weight per 100 parts by weight of monoolefin copolymer rubber) was dissolved in 432 g of toluene, and this was added to the autorotating reactor.

After that, impregnation was carried out in the same manner as in Example 1 at 60°C for 3 hours.
Crosslinking was carried out at 90°C for 5 hours to obtain partially crosslinked thermoplastic elastomer pellets. This product was further passed through a single-screw extruder and then subjected to the following evaluations.

Note that this example was a waterless system, and the total amount charged was about 60% of the reactor.

Gel fraction 77 [wt%] Hardness J-S
-A? 8 Tensile strength 120' (kg/c++!
) Tensile elongation 530 [%] Heating and pressing deformation rate 130°C1.5 [%] 150°C
5.5 [%] Q value 2.3 (Xl0-”QC/s
ee) No over-density gel Injection moldability Good permanganese acid strength Material consumption 0.12 (
p, plm) Comparative Example 1 The same types of monoolefin copolymer rubber and polyolefin resin as in Example 1 were used, and the blending ratio was also the same.
A partially crosslinked thermoplastic elastomer was produced using a conventional method (melt kneading dynamic crosslinking method).

8.4 kg (60 kg of ethylene/propylene/non-conjugated diene copolymer rubber (same as in Example 1)
parts by weight), polypropylene (same as Example 1)
5. e kg (40 parts by weight), and then added 1,3-bis-(t-butylperoxyisopropyl)benzene (trade name: Kayaku Nouri Co., Ltd., Parryoku Dox) at a concentration of 40% by weight as a crosslinking agent. and 40 g of dibenzothiazole disulfide as a crosslinking reaction retarder.
and 36 o'g of ethylene/polypylene copolymer rubber (propylene content 40% by weight, Mooney viscosity 50, no non-conjugated diene) containing a block of crosslinking agent obtained by kneading with a roll at 50°C for 2 minutes. Masterbatch 525g (monoolefin copolymer rubber 10', O parts by weight).

On the other hand, a pure crosslinking agent (1.25 parts by weight, the same as in the example) was added and kneaded for about 7 minutes for dynamic crosslinking. The temperature of Banbury Mixani at this time was about 220°C.

Next, this was taken out, made into a sheet with a roll, pelletized with a sheet cutter, and then partially crosslinked thermoplastic elastomer pellets were obtained with a single screw extruder, after which the following evaluations were performed. .

Gel fraction 91 [wt%] Q value
28 (XIO-3cc/5e
c) Overdense gel Comparative Example 2 Pyrene content: 32% by weight ζ Mooney viscosity: 62, dicyclopentadiene as non-conjugated diene, iodine number: 12,
(hereinafter referred to as 1cP-2) a, akg (6° parts by weight),
Comparative Example 1 was prepared using 6 kg (4' 0 parts by weight) of the same polypropylene as in Example 1 as the polyolefin resin.
A partially crosslinked thermoplastic elastomer was produced using a Banbury mixer in the same manner as above, and after the single screw extruder was damaged, the following physical properties were evaluated.

Gel fraction 92 [wt%] Hardness J engineering S-
A' 98 32- Tensile strength 11o (kg/cnt) Tensile elongation 380 [%] Heating and pressing deformation rate
130°C 4 (%) 1150°C19 [
%] Q value 26 (XI
0-3cc/sea) No overdense gel Injection moldability Good Potassium permanganate concentration substance 2.5 (p
, p, m) As is clear from the above Examples and Comparative Examples, the dynamic crosslinking method by melt kneading using a Banbury mixer (Comparative Examples 1 and 2) does not cause molecular cleavage of polypropylene by the crosslinking agent. This is large compared to Example 1.2.

It can also be seen that the properties of Examples 1 and 2 are far superior to those of Comparative Example 2.

Furthermore, by using an autorotating reactor, Example 1.2 of the present invention requires a dehydrator (centrifuge) and a dryer in addition to the reactor, compared to the prior art using a blade-stirred reactor. There is no need for special preparation, and there is little movement of products.
Furthermore, the weight ratio of resin to water filled in the reactor is high, and in some cases, it is possible to use a system without water as in Example 2. The resin amount) was 327.5 g, and in Example 2 it was 360 g.

On the other hand, in the blade-stirred reactor, when the weight ratio of the granular composite to water was 1/1, the amount of product per reactor 1 was 275 g, which was lower than in Example 1.2. Therefore, it can be seen that the manufacturing method of the present invention has high productivity and is streamlined in terms of process.

Example 3 (The monoolefin copolymer rubber, the polyolefin resin, and the blending ratio were the same as those in Example 1, using the same granular composite as in Example 1, and using benzoyl peroxide as a crosslinking agent at a ratio of 0.3 to the monoolefin copolymer rubber.
0 weight 1% 1 was dissolved in benzene (10 times the amount of the crosslinking agent), all other conditions were the same as in Example 1, and pellets of partially crosslinked thermoplastic elastomer were obtained using an autorotating reactor. Ta. This product was further passed through a single-screw extruder and then subjected to the following evaluations.

Gel fraction 46 [wt%] Hardness JIS-
A9'7 Tensile strength]-12 (ky/cJ:]
Tensile elongation 320 [%] Deformation rate under heat and pressure 130°C 8 [%] 1150°C 20 [%] No overdensity gel Injection moldability Good example 4 Monoolefin copolymer rubber, polyolefin resin and compounding ratio are as in Example A granular composite similar to 1 was used, and t-butylnoA↓? was used as a crosslinking agent. Kutoate (manufactured by Nihon Yushi Co., Ltd.,
2.50% by weight of Perbutyl 0 (trade name) based on the monoolefin copolymer rubber was dissolved in benzene (10 times the amount of the crosslinking agent), all other conditions were the same as in Example 1, and a self-rotating mold was used. A reactor was used to obtain partially crosslinked thermoplastic elastomer pellets. This product was further passed through a single-screw extruder and then subjected to the following evaluations.

Gel fraction 89 [wt%] - 5D - Hardness JIS-A9B Tensile strength 150 (kg/C+4) Tensile elongation 280 [%] Heating and pressing deformation rate
130°CO [%] 1150°C 3 [%] No overdensity gel Injection moldability Good Example 5 Ethylene-propylene-nonconjugated diene terpolymer rubber (propylene content 2) as monoolefin copolymer rubber
8% by weight, Mooney viscosity 51, ethylidene norbornene as non-conjugated diene, 15 as iodination, hereinafter BP-
3) and 90 parts by weight of propylene/ethylene block copolymer resin (MIF R1) as a polyolefin resin.
5g/l 0 minutes, ethylene content 8% by weight, hereinafter pp, j
Using a granular composite consisting of 10 parts by weight of benzoyl peroxide as a crosslinking agent, 0.72% by weight of benzene (referred to as
All other conditions were Example 136.
- Pellets of partially crosslinked thermoplastic elastomer were obtained using a rotating reactor.

This product was further passed through a single-screw extruder and then subjected to the following evaluations.

Gel fraction 51 [weight%'] Hardness JI
S-/171 Tensile strength q o (1(g/c++!
) Tensile elongation 23.0. C% ] Heating and pressing molding rate 130°C14 (% ) 1150°C 29
[%], No over-density gel Injection moldability Good Example 6 Same E as in Example 1 as mono-olefin co-electric and composite rubber
P-1, 10 parts by weight, polyolefin resin, propylene/hexene-1 random copolymer resin (M F
R'7g/10min, hexene-1 content 134~wt%,
Using a granular composite consisting of 90 parts by weight of benzoyl peroxide (hereinafter referred to as PP-3), 0.62 parts by weight of benzene (10 times the amount of the crosslinking agent) was added to 100 parts by weight of monoolefin copolymer rubber as a crosslinking agent. ), all other conditions were the same as in Example 1, and a partially crosslinked thermoplastic elastomer pellet was obtained using an autorotating reactor. This product was further passed through a single-screw extruder and then subjected to the following evaluations.

Gel fraction 93 [wt%] Hardness JIS-
A2B Tensile strength 210 (kg/c shoulder) Tensile elongation 6oo (%) Heating and pressing deformation rate 12 [%] Overdense gel
No injection moldability Good Example 7 In Example 2, the impregnation temperature and time were 60'C for 13 hours,
The crosslinking temperature and time were 110'C for 1 hour, and all other conditions and composition of the granular bonded material were the same as in Example 2 to obtain partially crosslinked thermoplastic elastomer pellets. This product was further passed through a single-screw extruder and then subjected to the following evaluations.

Gel fraction 79 [wt%] Hardness JIS-
A2B tensile strength ]-25 (kg/CT+!
) Tensile elongation 560 [%] Heating and pressing deformation rate 130°C1.3C%] 1150
°C5,0C%] Q value 2.5 (XI
O-'' cc/sec) No overdense gel Injection moldability Good As mentioned above, the quality of the obtained product was the same as that obtained in Example 2, and was good. In the method of the invention, especially in a water-free system,
High-temperature crosslinking exceeding °C is possible, and the crosslinking time can be further shortened from 5 hours to 1 hour compared to Example 2, and good productivity was confirmed from this point as well.

Applicant: Mitsubishi Yuka Co., Ltd. Agent: Patent attorney Katsura Atsuta

Claims (3)

[Claims] (1) A granular composite consisting of a monoolefin copolymer rubber and a polyolefin resin is impregnated with the required amount of crosslinking agent under conditions that the crosslinking agent is not substantially decomposed, and then,
In a method for producing a thermoplastic elastomer by partially crosslinking a granular composite by raising the temperature to a humidity at which decomposition of the crosslinking agent occurs, 0.3 to 20 parts by weight of granular composite material is added to 1 part by weight of the crosslinking agent. A solution in which a crosslinking agent is dissolved in a solvent that can be impregnated into the composite is mixed with the granular composite either as it is or suspended in water equal in weight or less to the granular composite, and the crosslinking agent is uniformly impregnated with the granular composite. 1. A method for producing a thermoplastic elastomer, the method comprising: heating the mixed system to carry out a crosslinking reaction. (2) The method according to claim (1), wherein the mixed impregnation of the particulate composite and the crosslinking agent and the crosslinking reaction are carried out while the reaction vessel is moved or shaken. (3) The mixed impregnation of the crosslinking agent and the crosslinking reaction are carried out using a suspension in which the crosslinking agent is dispersed in water of 1/2 or less of the weight of the granular composite; or 2nd (2nd
).