WO2001070875A1

WO2001070875A1 - Process for producing thermoplastic styrene elastomer composition

Info

Publication number: WO2001070875A1
Application number: PCT/JP2001/002347
Authority: WO
Inventors: Atsushi Yamada; Shino Nakanishi
Original assignee: Asahi Chemical Synthetic Co., Ltd.
Priority date: 2000-03-24
Filing date: 2001-03-23
Publication date: 2001-09-27

Abstract

A process for efficiently producing at a low equipment cost a thermoplastic styrene elastomer composition having excellent sealing performances. It comprises the step of dissolving, with heating, 100 parts by weight of a thermoplastic styrene elastomer in 200 to 4,000 parts by weight of a liquid softener in a mixing tank having a stirring means.

Description

Description Method for producing styrene-based thermoplastic elastomer composition

The present invention relates to a method for producing a styrenic thermoplastic elastomer composition. More specifically, an excellent method for producing a styrenic thermoplastic elastomer composition suitable for a sealing material.

In recent years, with the development of polymer synthesis technology, in all fields of the industry, conversion to new materials that are superior in cost and performance has been promoted in place of conventional materials. For example, in the field of rubber products, conventional vulcanized rubber is manufactured by kneading raw rubber with a reinforcing agent and a vulcanizing agent, and then using a lot of labor and energy through the molding vulcanization process. With the advent of thermoplastic elastomers, which can be processed and molded on thermoplastic molding machines, are being replaced by thermoplastic elastomers in many application fields.

In the field of sealing materials, various sealing materials are used to maintain the tightness of joints of containers, buildings, various molding machines, and the like. As the sealing material, a material having rubber elasticity as its characteristic is often used, and in the past, molded products such as vulcanized rubber, soft vinyl chloride resin, and polyurethane were used, but in recent years, elastomers have been used. A series of hot melt-type polymers are also being used.

In addition, even in the field of sealing materials that require rubber properties at high temperatures, vulcanized rubber molded products and synthetic resin foam products require a lot of time and effort to install, and cost reductions do not progress. Practical use of hot-melt type seal materials of thermoplastic elastomer that can be mounted by fusion has been gradually attempted. These thermoplastics A composition used for a sealing material of a type of an elastomer has also been proposed (Japanese Patent Application Laid-Open No. Hei 7-50666, Japanese Patent Laid-Open No. Hei 11-323026).

Thermoplastic elastomer-type sealing materials have excellent processability and properties suitable for sealing materials.However, for mixing compounding components, kneaders, Banbury mixers, screw extruders, twin-screw extruders, etc. Kneading and mixing equipment was required, and equipment costs were high and manufacturing workability was difficult.

The present inventors have reached the present invention as a result of pursuing a technique for producing a thermoplastic elastomer composition exhibiting excellent performance as a sealing material with good workability at low equipment cost. Disclosure of the invention

An object of the present invention is to provide a method for producing a thermoplastic elastomer composition exhibiting excellent performance as a sealing material with good workability at low equipment cost. According to the present invention, a styrene-based thermoplastic elastomer is added to 200 to 400 parts by weight of a liquid softener with respect to 100 parts by weight of the elastomer, in a mixing tank having stirring means, There is provided a method for producing a styrenic thermoplastic elastomer composition comprising a step of dissolving under heating.

A styrene-based thermoplastic elastomer is dissolved in 200 to 300 parts by weight of a liquid softener with respect to 100 parts by weight of the elastomer in a mixing tank having stirring means under heating. A method for producing a styrenic thermoplastic elastomer composition comprising a step is a preferred embodiment of the present invention.

A preferred embodiment of the present invention is a method for producing a styrene-based thermoplastic elastomer composition in which the styrene-based thermoplastic elastomer is dissolved in the liquid softener and then a tackifier is added.

A production method in which the dissolution is performed at a temperature exceeding 200 ° C. is also a preferred embodiment of the present invention.

The styrenic thermoplastic elastomer is styrene-isoprene-styrene A production method which is at least one selected from a lock copolymer, a styrene-butadiene-styrene block copolymer, and a hydrogenated product or a carboxyl-modified product thereof is a preferred embodiment of the present invention.

A production method in which the intrinsic viscosity [77] of the styrenic thermoplastic elastomer is 1 dl Zg or more is a preferred embodiment of the present invention. Specific modes for carrying out the invention

The present invention provides a styrene-based thermoplastic elastomer having a liquid softening ratio of 200 to 400 parts by weight, preferably 200 to 300 parts by weight, based on 100 parts by weight of the elastomer. A method for producing a styrene-based thermoplastic elastomer composition, comprising a step of dissolving an agent under heating in a mixing tank having a stirring means.

Styrenic thermoplastic elastomer

The styrene-based thermoplastic elastomer of the present invention refers to a thermoplastic elastomer containing styrene, a homologue thereof, or an analog thereof. Those known as styrene-based thermoplastic elastomers can be used without any particular limitation. As a specific example, a block copolymer containing a block of styrene, a homologue thereof or an analog thereof as at least one terminal block, and containing at least one elastomer block of a conjugated gen or a hydrogenated product thereof as an intermediate block. Coalescence can be mentioned.

Preferred specific examples of the styrene-based thermoplastic elastomer of the present invention include styrene-butadiene block copolymer (S_B), styrene-butadiene-styrene block copolymer (S—B—S), and styrene-isoprene block copolymer— (S—1). ), Styrene-isoprene-styrene block copolymer (S-I-s), styrene-butadiene / isoprene (random copolymer block of butadiene and isoprene) block copolymer (S-B / I), styrene-butadiene isoprene Styrene-containing block copolymers such as styrene-block copolymers (S-B / I-S); styrene-butadiene-styrene block copolymers Hydrogenated products of these block copolymers such as hydrogenated products (SEBS) and hydrogenated products of styrene-isoprene-styrene block copolymers (SEPS); carboxyl-modified products such as maleic anhydride-modified products of these block copolymers. it can. Further, the styrene block may contain, in addition to styrene, a copolymer of styrene and an aromatic vinyl compound such as hexamethylstyrene.

Among these styrene-based thermoplastic elastomers, styrene-isoprene-styrene block copolymers, styrene-butadiene-styrene block copolymers, and hydrogenated or carboxyl-modified products thereof are preferably used. The styrenic thermoplastic elastomer of the present invention may be used alone or as a mixture of two or more.

The proportion of the styrene monomer unit in the styrenic elastomer of the present invention is 5 to 70% by weight, and from the viewpoint of the balance between flexibility and rubber elasticity, the proportion is preferably 20 to 40% by weight. .

The styrenic thermoplastic elastomer of the present invention preferably has an intrinsic viscosity [? 7] of 1 or more, preferably 1 to 10 and more preferably 1.2 to 6. The intrinsic viscosity [? 7] in the present invention refers to a value measured in decalin at 135 ° C.

The composition according to the present invention comprises the specific styrenic thermoplastic elastomer 10

It contains 200 to 400 parts by weight of liquid softener per 0 parts by weight. A more preferred amount of the liquid softener is 100 parts by weight of the styrene-based thermoplastic elastomer.

200 to 400, preferably 200 to 300 parts by weight, more preferably 3

It is preferably from 300 to 300 parts by weight, and more preferably from 500 to 2000 parts by weight.

Liquid softener

In the present invention, examples of the liquid softener used include at least one selected from the group consisting of process oils, liquid rubbers, and modified products thereof. Specifically, process oils such as paraffin oil, naphthenic oil, and aloma oil; liquid polyisoprene, liquid polybutene, liquid Liquid rubbers such as polybutene, liquid 1,2 polybutadiene, and liquid styrene-butadiene rubber; modified products such as maleated polybutene, terminal hydroxyl group polybutene, and maleated polybutene; The liquid softener is used alone or in combination of two or more.

Of these, preferred liquid softeners include process oils, especially paraffin oils.

In addition, components usually used as liquid tackifiers, for example, rosin ester, modified rosin ester, terpene low polymer, modified terpene low polymer, C5 liquid petroleum resin, C5 to C9 liquid petroleum resin And the like can be used as the liquid softener of the present invention. In the case where this liquid tackifier is used, the composition to be selected has an even higher adhesiveness to the adherend, so that the composition can be used when the adhesiveness to the adherend is required.

Styrene-based thermoplastic elastomer composition

The styrenic thermoplastic elastomer composition of the present invention comprises the aforementioned styrenic thermoplastic elastomer in an amount of 200 to 400 parts by weight, preferably 200 to 100 parts by weight of the elastomer. It can be produced by dissolving in ~ 300 parts by weight of a liquid softener under heating in a mixing tank. In producing the composition, the following components can be arbitrarily mixed and used depending on the properties of the desired composition. These other components can be added to the styrenic thermoplastic elastomer and the liquid softener at any stage, but preferably mixed after dissolving the styrenic thermoplastic elastomer in the liquid softener. Is the way.

In addition, “dissolve” in the present invention means to make a state that can be visually recognized as uniform.

The material of the mixing tank used in the present invention is not particularly limited, and a conventionally known tank can be used. For example, a cylindrical SUS reactor is preferably used.

The mixing tank of the present invention preferably includes a stirring means. As a stirring means, a stirring blade is generally used, but other means having a stirring effect may be employed. Can be. The shape and size of the stirring blade can be appropriately selected.

The shape of the stirring blade can be of a caliper type, a propeller type, a high discharge type propeller type, a paddle type, a turbine type, a ribbon screw type, or the like.

In the present invention, the styrene-based thermoplastic elastomer is dissolved in a liquid softener under heating. While under heating, the temperature is not particularly limited, but a preferable temperature is a temperature exceeding 200 ° C, more preferably a temperature exceeding 200 ° C and 240 ° C or less, Preferably, it is 220 ° C to 240 ° C.

Further, the present invention can be carried out in an atmosphere of an inert gas such as nitrogen to avoid an oxidation reaction.

A composition having the following conditions in the composition of the present invention can be more preferably used.

(a) the softening point measured by the ring and ball method softening point measurement method is 120 to 230 ° C;

(b) No cracking occurs when a compressive strain of 75% or more is applied in an atmosphere of −30 ° C. to 40 ° C .;

(c) Flow is small when left unloaded for 24 hours in an atmosphere of 100 ° C. A tackifier can be added to the composition of the present invention to further improve the tackiness. Examples of the tackifier include an aliphatic hydrogenated woodpecker, a resin, a modified rosin, or an ester thereof, an aliphatic petroleum resin, an alicyclic petroleum resin, an aromatic petroleum resin, an aliphatic component and an aromatic substance. Any known tackifiers such as copolymerized petroleum resin of group III component, styrene resin containing styrene and / or polystyrene, isoprene resin, alkylphenol resin, terpene resin, and coumarone'indene resin Used without. Above all, styrene-based resin, rosin-based and petroleum resin-based tackifiers are preferred, and styrene-based resin is particularly preferred. Specific examples of styrene-based resin include styrene, permethylstyrene, and methylated styrene. Styrene analogs or homologues such as monocyclic styrenes, etc., polymerized singly or in combination, and those styrenes, analogs or homologues thereof, aliphatic petroleum resins, alicyclic petroleum resins, aromatics Examples include those obtained by copolymerizing petroleum resins.

It can be appropriately selected and used from those commercially available as styrene.

When a styrene-based resin is used as a tackifier, not only does the composition have improved tackiness, but also the glass transition point of the composition is increased, resulting in an effect of increasing the softening point of the composition. Improvement of the softening point is a preferable effect because it improves the thermal fluidity of the sealing material.

Further, the composition of the present invention may contain a modifier such as a polyolefin wax, an inorganic and / or organic filler, or an additive such as a pigment or a stabilizer, as long as the object of the present invention is not impaired. it can.

Examples of the wax include paraffin wax, microcrystalline phosphorus wax, polyethylene wax, polypropylene wax, Fischer-Tropx, polyethylene oxide wax, maleated polyethylene wax, and modified products thereof.

Examples of thermoplastic elastomers and thermoplastic resins include styrene-butadiene rubber, ethylene-propylene rubber, butyl rubber, acrylic rubber, ethylene-vinyl acetate copolymer, polyethylene, polypropylene, polystyrene, polybutene, and borbutadiene. Here is an example.

Inorganic fillers include inorganic fibers and inorganic foams such as calcium carbonate, zinc oxide, glass beads, titanium oxide, alumina, carbon black, clay, ferrite, talc, mica powder, aerosil, silica, and glass fiber. The body is illustrated.

Examples of the organic filler include powder of a thermosetting resin such as an epoxy resin, carbon fiber, synthetic fiber, and synthetic pulp. Examples of the stabilizer include a phenol-based antioxidant, a phosphorus-based antioxidant, a benzotriazol-based ultraviolet absorber, a benzophenone-based ultraviolet absorber, and a hinderdamine-based radical scavenger.

When dissolving styrenic thermoplastic elastomers in liquid softeners at elevated temperatures, the use of stabilizers is recommended to reduce the degradation of the polymeric material due to temperature. In the method using a kneading mixer such as a kneader, which is a conventionally known mixing method, not only is the equipment cost high, but also a strong shearing force is applied, so that the polymer chains may be broken and quality may be changed in the manufacturing process. However, these problems can be solved at once by implementing the present invention.

Specific embodiments of the present invention are shown in Examples described later. Examples of preferred embodiments include a styrene-isoprene-styrene block having an intrinsic viscosity [77] of 1 d 1 / g or more. A copolymer, a styrene-butadiene-styrene block copolymer, and a styrene-based thermoplastic elastomer such as a hydrogenated product or a modified propyloxyl product thereof were added to 200 parts by weight of the elastomer. 0 to 400 parts by weight, preferably 200 to 300 parts by weight, of a liquid softening agent such as paraffin oil is heated in a mixing tank equipped with a stirrer, preferably at 200 ° C. This is a method of producing a styrene-based thermoplastic elastomer composition by dissolving at a temperature higher than the above, and then adding a tackifier such as a styrene-based sunsetfire.

The styrenic thermoplastic elastomer composition obtained according to the present invention has low compression set and excellent adhesion to adherends, but also has good peelability, so that it has excellent on-site workability. It is a composition suitable for a sealing material.

As the sealing material, any material generally applicable to gaskets, packing, sealing, coking, putty and the like can be used. In particular, it is suitably used for sealing various lamps, sealing for building materials such as window frames, and the like. Further, it can be suitably used as a sealing material for concrete moldings. Example

Hereinafter, the present invention will be described with reference to more specific examples, but the present invention is not limited to these examples.

In the present invention, each physical property of the hot melt composition was measured by the following methods. Preparation of test piece: A cylinder having a height of 20 mm and a diameter of 27 mm was formed from the hot melt composition to obtain a test piece.

(1) Melt viscosity

It was measured with a BF-type automatic viscometer. The hot melt composition was placed in a cylindrical metal chamber, melted sufficiently at 220 ° C, and the No. 29 spindle was attached to the measuring instrument. Thereafter, the spindle was immersed in the chamber in which the hot melt composition was melted, and the spindle was rotated at a rotation speed of 5.0 rpm. At that time, the viscosity was determined by a viscometer from the resistance applied to the spindle.

(2) Ring and ball softening point

It was measured in accordance with JAI-17-171991.

(3) Cracking at 75% compression

Using a precision universal testing machine equipped with a thermostat (Autograph AG-200000 C, manufactured by Shimadzu Corporation) at a compression speed of 50 mm / min, ambient temperature of 40 ° C and -30 ° C,

The test piece was compressed 75% in the height direction and immediately opened. Thereafter, the presence or absence of cracks was visually observed. The results were displayed as follows.

〇: No crack was generated.

X: Cracking had occurred.

(4) Liquidity

The test piece was left in a constant-temperature bath at an ambient temperature of 10 oC for 24 hours with no load so that the height direction was perpendicular to the horizontal plane, then removed, and the projected area on the lower surface of the test piece was measured. It measured and calculated the change (increase) rate from the projection area before leaving. The fluidity was determined according to the following criteria. 〇: The change ratio from the projected area was less than 10%.

X: The change ratio from the projected area was 10% or more.

(5) 50% compressive stress

The test piece was compressed by 50% in the same manner as the crack test at 75% compression, and the compressive stress at that time was measured. It was expressed as stress / cross-sectional area (Kg / cm ² ).

(6) 50% compression set

In the same way as in the test for cracking at 75% compression, with the test piece compressed at 50%, placed at 50 C and 80 ° C for 24 hours, opened, and left at 20 ° C for 22 hours Was measured. The rate of change (decrease) from the height before measurement was expressed in%.

The hot melt composition was applied on a glass plate surface in a circular shape with a width of about 1 cm and a height of about 0.3 cm, and then compressed 50% with another glass plate. In that state, it was left in water at 80 ° C for 10 days, and the presence or absence of water intrusion was observed. The observation results were displayed as follows.

〇: Water intrusion was not recognized.

X: Intrusion of water was recognized.

(Example 1)

500 g of paraffin oil (Diana Process ^OilTM PM-90, Idemitsu Kosan Co., Ltd.) was charged as a liquid softening agent into a mixing tank with an internal volume of 2000 ml equipped with a stirrer with iris-type stirring blades, and the temperature was raised to 200 ° C. after temperature, [??] is 1.46 for steel Len - isoprene one styrene block copolymer hydrogenated product (SEPS) (concept down ^TM 4055, manufactured by Kuraray Co., Ltd.) was 100 g added, 200 ° C 30 Stir for a minute to dissolve.

Subsequently, 100 g of a styrene-vinyltoluene copolymer styrene-based Yutsuki Fire (ENDEX ™ 155 Hercules) was added, and the mixture was further stirred for 30 minutes to obtain about 700 g of a hot melt composition. Table 1 shows the physical properties of the obtained composition. (Example 2)

In the same manner as in Example 1, except that the stirring condition for dissolving the hydrogenated styrene-isoprene-styrene block copolymer (SEPS) was set at 210 ° C for 45 minutes, the hot melt composition was reduced to about 70 Og. Obtained. Table 1 shows the physical properties of the obtained composition.

(Example 3)

In place of the hydrogenated product of styrene-isoprene-styrene block copolymer used in Example 1, [] was hydrogenated product of styrene-isoprene-styrene block copolymer having 1.26 (SEPS) (Septon ^™ 2006 Kuraray) was used, except that about 700 g of a hot melt composition was obtained in the same manner as in Example 1. Table 1 shows the physical properties of the obtained composition.

(Examples 4 to 7)

A hot melt composition was obtained in the same manner as in Example 1, except that the amount of paraffin oil was changed to 600 g, 800 g, 1000 g, and 3000 g, respectively. Table 1 shows the physical properties of the obtained composition.

(Comparative Example 1)

The same amount of paraffin oil used in the experiment, 30 g, hydrogenated styrene-isoprene-styrene block copolymer (SEPS), 100 g, and styrene-based evening Tsukii Fire 100 g, a 1-liter double-armed doubler (Model SV-1GH-1 type) and kneaded at 52 rpm, 190 ° C for 1 hour to obtain about 230 g of hot melt composition. Table 1 shows the physical properties of the obtained composition. t to

o Table 1

^ 关; raciwSAi 1

1 夹失 Loss ffiWI Loss (CL¾1r! 1 Thermoplastic SEPS ([V] 1.46) 100 100 too inn 100 100 100

Pair last inn

SEPS ([r;] 1.26)

g 500 500 500 600 800 1000 3000 30

Liquid softener process oil

0

Tackifier Styrene type 10 100 100 100 100 100 100 100

Firer

Q K (\ f

Melt viscosity (mPa's)

Ring and ball softening point CC) 1/0 1/0 1/0 1 IK) 140 1 A

185 or less

40 days

7 5% cracking at compression

Thing Cs

-30 〇〇〇〇〇〇 X o X

Liquidity 〇〇〇〇〇〇〇〇

50% compressive stress (KgZcm ² ) 0.6 0.6 0.7 0.6 0.5 0.4 0.1 23.0

50. C 40 40 35 40 30 20 15 70

50% compression strain (06)

80 to 80 80 75 80 75 65 30 95

Nectar 〇〇〇〇〇〇〇 X

Industrial applicability

The present invention provides a method for producing a desired thermoplastic elastomer composition with low equipment cost and good workability by producing a specific thermoplastic elastomer composition under specific conditions.

Claims

The scope of the claims

1. The styrene-based thermoplastic elastomer was added to 200 to 400 parts by weight of a liquid softening agent with respect to 100 parts by weight of the elastomer in a mixing tank having stirring means under heating. A method for producing a styrenic thermoplastic elastomer composition, comprising a step of dissolving.

2. The method according to claim 1, wherein the amount of the liquid softening agent is from 200 to 300 parts by weight based on 100 parts by weight of the styrene-based thermoplastic elastomer.

3. The styrene-based thermoplastic elastomer is at least one selected from a styrene-isoprenestyrene block copolymer, a styrene-butadiene-styrene block copolymer, and a hydrogenated product or a carboxyl-modified product thereof. 3. The production method according to claim 1 or 2.

4. The method according to any one of claims 1 to 3, wherein the intrinsic viscosity [77] of the styrenic thermoplastic elastomer is 1 d1 / g or more.

5. The method according to any one of claims 1 to 4, wherein the liquid softener is a process oil.

6. The method according to any one of claims 1 to 5, wherein the melting is performed at a temperature exceeding 200 ° C.

7. The method according to any one of claims 1 to 6, wherein the styrenic thermoplastic elastomer is dissolved in the liquid softener, and then a tackifier is further added.

8. The method according to claim 7, wherein the tackifier is a styrene resin.