CA1300776C - Moldable block copolymer resin composition - Google Patents

Moldable block copolymer resin composition

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Publication number
CA1300776C
CA1300776C CA000538842A CA538842A CA1300776C CA 1300776 C CA1300776 C CA 1300776C CA 000538842 A CA000538842 A CA 000538842A CA 538842 A CA538842 A CA 538842A CA 1300776 C CA1300776 C CA 1300776C
Authority
CA
Canada
Prior art keywords
weight
block copolymer
copolymer
block
resin composition
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
CA000538842A
Other languages
French (fr)
Inventor
Masahiro Hotta
Tadasu Inoue
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Dainippon Plastics Co Ltd
Original Assignee
Dainippon Plastics Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Dainippon Plastics Co Ltd filed Critical Dainippon Plastics Co Ltd
Priority to CA000538842A priority Critical patent/CA1300776C/en
Application granted granted Critical
Publication of CA1300776C publication Critical patent/CA1300776C/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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  • Extrusion Moulding Of Plastics Or The Like (AREA)
  • Compositions Of Macromolecular Compounds (AREA)

Abstract

ABSTRACT OF THE DISCLOSURE

A resin composition comprising a block copolymer which comprises an intermediate block of a hydrogenated conjugated diene polymer and terminal blokcs of an aromatic vinyl. compound polymer, the composition being characterized in that the composition comprises:
(a) 20 to 90 parts by weight of a block copolymer having terminal blocks in an amount of about 10 to about 20% by weight based on the copolymer (a), and (b) 80 to 10 parts by weight of a block copolymer mixed with the copolymer (a) and having terminal blocks in an amount of about 25 to about 35% by weight based on the copolymer (b).

Description

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BACKGROtJND OF THE INVENTIO~
1. Field of the Invention The present invention relates to a resin composition, and more particularly to a polymer composition which is excellent in softness, transparency and moldability or shapability.
2. Description of the Prior Art Moldinq resin materials having excellent soft-ness and transparency recently used include block copolymers which comprise an intermediate block (about 5,000 to about 125,000 in number average molecular weight) of a hydro-genated conjugated diene polymer, such as ethylene-butylene copolymer or ethylene-propylene copolymer, and terminal blocks (about 10,000 to about 300 ,oao in number average molecular weight) of an aromatic vinyl compound copolymer, such as polystyrene (U.S.P. Nos. 4,140,162 and 4,588,777).
Such block copolymers are obtained usually by .
the hydrogenation of block polymers having the structure of (vinyl aromatic polymer block)-(.conjugated diene polymer block)-(vinyl aromatic polymer block), such as polystyrene-., . ' : ' ;

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polybutadiene-polystyrene structure or polystyrene-polyisoprene-polystyrene structure. The degree of hydrogenation of the conjugated diene polymer block is at least 90%. Although it appears likely that the aryl of the vinyl aromatic polymer blocks will also be hydrogenated during the hydrogenation, the degree of hydrogenation thereof is less than 10% if highest.
Thus, it is thought that the conjugated diene polymer block is substantially subjected to hydrogenation.
However, these block copolymers are not satifactorily moldable by extrusion or injection when singly used. For example, the block copolymer, when in the form of particles, powders or fla]ces, is difficult to make into molding pellets Ol^ is in no way extrudable into sheets or tubes. Actually, thereore, such block copolymers are used as spread in the form of a flowable organic solvent solution, or as blended with some other resin such as polyolefin, or as mixed with plasticizers, oils, etc. into a moldable composition.
Nevertheless, the spreading of the copolymer in the form of a solution needs a cumbersome procedure and further requires much labor and cost for completely removing the residual solvent. Blending with other resin or addition of plasticizer, oil and the like alters the properties such as transparency, softness and strength, not infrequentl~ giving a composition which is un-satisfactory for the contemplated use.
Accordingly, it has been desired to provide a resin material which retains the excellent properties of the block copolymer ln respect of transparency, softness, strength, etc. and which nevertheless has high moldability or shapability.
The present invention has been accomplished in view of these problems.
While a block copolymer (a) having terminal blocks in an amount of about 10 to about 20~ by weight based on the copolymer is used alone, it was actually impossible to prepare pellets from this copolymer by a continuous operation because when pellets were to be prepared by extr.usion, the copolymer exhibited high tackiness and low viscosity, re.ndering the resulting strands difficult to take up. Further even if the copolymer was extruded throuyh a T-die or tubular die, it was impossible to continuously wind up the extrudate. Thus, it was impossible to extrude the copolymer directly into sheets or tubes. While a block copolymer (b) which comprises terminal blocks in an amount of about 25 to about 35% by weight based on the copolymer (b) is used alone, problems were also ~3C~0'7~

encountered with this copolymer. When the copolymer was extruded for the preparation of pellets, the resulting strands were markedly rough-surfaced, developing numerous large crevices in an extreme case, so that it was actually difficult to prepare pellets. Accordingly, it was totally impossible to extrude the copolymer into tubes or sheets.
We have conducted intensive research and various experiments in order to improve the moldability or extrudability of the foregoing block copolymers and consequently discovered the surprising fact that whereas the bloclc copolymer (a) and the block copolymer (b) fall into the category of the foregoing block copolymers and were not actually extrudable when singly used, these copolymers (a) and (b) e~hibit excellent moldability or e~trudability when used in combination. The present invention has been accomplished based on this finding.
SUMMARY OF THE INVENTION
In a broad aspect, the present invention relates to a resin composition comprising a blend of: (a) 20 to 90 parts by weight of a Pirst block copolymer having terminal blocks in an amount o~ about 10-20% by weight based on the weight of the first block copolymer; and (b) 80 to 10 parts by weight of a second block copolymer having terminal blocks in an amount of about 25-35% by weight based on the weight of the second block copolymer; said first and second block copolymers each comprising an intermediate block of a hydrogenated conjugated diene polymer having a number 3~ /

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average molecular weight of about lO,000 - 300,000 and terminal blocks of an aromatic vinyl polymer having a number average molecular weight oE about 5,000 - 125,000, the intermediate blocks of said block copolymers being at least 95~ hydrogenated, wherein the total of said first block copolymer and said second block copolymer is equal to 100 parts by weight.
The resin composition of the invention exhibits excellent moldability without necessitating any other particular polymer component, plasticizer, oil or the like and is useful for preparing various extruded or molded articles of which transparency, softness, weather resistance, etc., are required.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Examples of conjugated diene polymers for ~orming on hydrogenation the intermediate bloak oE the block copolymers to be used in the invention are polybutadiene, polyisoprene, polyahloroprene and the like which are about 10,000 to about 300,000, preforably about 30,000 to about 200,000, in number average molecular weight. Among these examples, polybutadiene and polyisoprene are desirable.
Aromatic vinyl compound polymers constituting both terminal blocks of block copolymers use~ul for the invention include styrene polymers such as polystyrene, poly-~-methylstyrene B

-' 3L30~3'7 t~

poly-p-methylstyrene, polychlorostyrene and the like, which are preferably 5,000 to 125,000, more preferably about 10,000 to about 60,000, in number average molecular weight. The most preferable of these examples is polystyrener The block copolymers are preferably about ; 20,000 to about 400,000, more preferably about 40,000 to about 300,000, in overall number average molecular weight.
Among such block copolymers, it is desirable from the viewpoint of heat resistance,weather resistance, etc. to use those which have been fully hydrogenated, such that the intermediate block thereof is at least 95~ in the degree of hydrogenation. In the case where the intermediate block is, for example, polybutadiene, this block s~lbstantially has the structure o ethylene-butylene copolymer when hydrogenated. In the case where the intermediate block is polyisoprene, the block sub-stantially has the structure of ethylene-propylene copolymer when hydrogenated.
According to the present invention, two kinds of block copolymers (a) and (b) are used. The block copolymer (a) comprises about 10 to about 20% by weight of terminal blocks based on the copolymer. The block copolymer (b) comprises about 25 to about 30% by " ~3Q~J~'7~

weight of terminal blocks based on the copolymer (b).
When the block copolymer (a) comprises less than 10 by weight of terminal blocks, the resulting compo-sitlon exhibits excessive tackiness when in a molten state and is therefore difficult to mold or extrude continuously, whereas if the terminal block content is in excess of 20% by weight, the composition fails to afford a smooth-surfaced extrudate and is therefore un-suited. On the other hand, when the block copolymer (b) comprises less than 25% by weight in terminal block content, the composition is excessively tacky while in a molten state and is difficult to extrude continuously.
When the content exceeds 35% by weight, the composition gives a markedly rough-surfaced extrudate and a product of undesirable softness and transparency. Most preferably, the combined terminal block proportion is 12 to 18~ by weight for the block copolymer (a) or 26 to 32~ by weight for the block copolymer (b). The components (a) and (b) may each comprise a mixture of copolymers.
Further the ratio,(a): (b), of the block copolymer (a) to the block copolymer (b) is suitably 20 - 90 parts by weight: 80 - 10 parts by weight (the combined amount: 100 parts by weight). If the amount of the block copolymer (a) is less than 20 parts by weight, the composition provides a markedly rough-surfaced ~ ~3~V~7~

extrudate and is unable to form a smooth-surfaced sheet by extrusion. When the amount exceed 90 parts by weight, the composition exhibits greatly increased tackiness and is not continuously extrudable into pellets or sheets. Most pre-ferably, the (a):(b) ratio is 25 - 80 parts by weight:75 -20 parts by weight.
The block copolymer (a) is readily available, for example, under the brand name and with the grade number of KRATON~G-1657, and the block copolymer tb), KRATON~G-1650 or -1652 (both products of Shell Chemical Co.) or Tuftec HR-1041 (product of Asaki Chemical Co., JAPAN).
The mixture of the block copolymers (a) and (b) in the above-specified ratio is readily extrudable into pellets in a molten state, whereas the conventional copolymers were dificult to extrude into pellets. The resultlng pellets can be easily made into smooth-surfaced transparent and sot sheets or tubes or various other shaped products using a usual extruder or injection molding machine. Preferably, the mix~ure is prepared by a known kneader or blender.
It is Eurther possible to incorporate into the resin composition of the invention small amounts of other resins (up to about 5% if largest), plasticizers, antiblocking agents, thermal stabilizers, antioxidants, ultraviolet absorbers, lubricants, coloring agents, etc.
insofar as such substances will not be detrimental to the ~r~

13~'776 effect achieved by the invention.
The present composition is usable for various industrial materials, household articles, etc. because of its transparency, softness and weather resistance.
More specifically, the present composition is usable for molding or extruding tubes such as tubes for piping systems for cleaning electronic parts, dehumidifier tubes, tubes for medical devices and apparatus, vender piping tubes, etc. and or extruding sheets such as lining or laminating materi.als for garment fabrics, intermediate resin layers for composite glass sheets, belt backings, etc.
Accordingly, the present invention also provides such molded or extruded products o various types.
The present invention will be described with r~ference to the following examples, which, however, in no way limi~ the invention.
Example 1 In a Henschel mixerj 70~ by weight of KRATON G-1657 (product of Shell Chemical Co., composed of poly-styrene terminal blocks and a hydrogenated intermediateblock of ethylene-butylene copolymer in the former-to-latter weight ratio of 14/86) serving as the component (a) and 30% by weight of KRATON*G-1650 (product of Shell Chemical Co., composed of terminal blocks of polystyrene and a hydrogenated intermediate block of * Denotes Trade Mark _ g _ ~13~)7~
, , .

ethylene-butylene copolymer in the former-to-latter weight ratio of 28/72) serving as the component (b) were mixed together at room temperature and then extruded under the followins conditions to prepare pellets. The operation was carried out smoothly with no problem.

Cylinder temperature ( C) Die temperature ( C) Cl C2 3 The pellets were extruded into a sheet under the following conditions by an extruder having a diameter of 40 mm and equipped with a coat hanger type die.
Screw ~/d: 28 Compression ratio: 4.0 Cylinder temperature ( C) Cl 210 Adapter temperature ( C): 240 Die temperature ( C) Take-up roll temperature ( C): 60 The sheet obtained was about 0.4 mm in thickness, Q077~i highly transparent, colorless and soft and had rubberlike elasticity.
When it was attempted to prepare pellets only from the above component (a), it was impossible to continuously take up the s-trands owing to high tackiness and low viscosity. When it was further attempted to prepare pellets from the component (b) alone, the strands obtained had numerous large crevices in its surface, failing to give pellets.
Example 2 The same components (a) and (b) as used in Example 1 were mixed together in varying ratios to prepare pellets and sheets~ The resul~s are given below.

Extrudability into pellets E~trudability into sheet No. Component Continuous Surface state Continuous Surface state ta) (b) take up take-up __ _ 1 10 9C Impossible Numerous large crevices 2 15 85 " Crevices 3 20 80 Possible Rough Possible Good 4 40 60 " Good Possible "

6 80 20 " " " "

7 90 10 " Slightly rough Possible "

8 95 5 Impossible Rough Impossible ~ood ~ ~L3(~W~i As the proportion of the component (b) increased, the mixture exhibited higher viscosity in a molten state, so that the extrusion temperature was set to a gradually slightly elevated level.
Compositions No. 3 to No. 7 are within the scope o~ the invention, while compositions No. 1, No. 2 and No. 8 are outside the scope of the invention. When preparing sheets from compositions No. 3 and No. 7, the distance between the die outlet and the take-up roll was reduced.
This made it possible to continuousl~ take up the resulting sheet.
Exam~le 3 KRATON G-1657 serving as the component (a) and KRATON G-1652 (the same as ICRATON G-1650 in compositlon but lower in molecular weight) serving as the component (b) were rnixed together in varying ratios in an attempt to prepare pellets and sheets. The results are listed below.
Since each composition was lower than the corresponding composition in Example 2 in melting temperature, the extrusion temperature was set to about 10 C lower level.

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E~trudability into pellets Extrudability into sheet No. Co Continuous Surface state Continuous Surface state (a) (b) take-up take-up 1 0 100 Impossible Numerous large crevices 2 10 90 " "
3 15 85 " Many crevices 4 20 80 Possible Rough Possible Good 5 40 60 " Good Possible "
6 60 40 " " " "
7 80 20 " " " "
8 90 10 " Slightly rough Possible "
9 95 5 Impossible very rough Impossible Good Compositions No. 4 to No. 8 are within the scope of the invention, while compositions No. 1, No. 2, No. 3 and No. 9 are outside the scope.

Comparative Example KRATON G-1650 and KRATON G-1652, both falling in-to the category of component (b),were mixed together in the ratio of 50/50 in an attempt to prepare pellets.
However, the strands obtained had crevices in the surface, were markedly rough-surfaced and could not be continuously taken up.
Example 4 An 80% by weight of KRATON G-1657, 20% by weight 3~7~

of KRATON G-1650 and stearic acid in an amount of 0.2 part by weight per 100 parts by weight of these resins were mixed together and made into pellets. The pellets were extruded into a tube under the following conditions.
Cylinder temperature ( C) Die temperature ( C) Cl C2 C3 The tube obtained was transparent and soft and had a smooth glossy surface.

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Claims (5)

1. A resin composition comprising a blend of:
(a) 20 to 90 parts by weight of a first block copolymer having terminal blocks in an amount of about 10-20% by weight based on the weight of the first block copolymer; and (b) 80 to 10 parts by weight of a second block copolymer having terminal blocks in an amount of about 25-35% by weight based on the weight of the second block copolymer;
said first and second block copolymers each comprising an intermediate block of a hydrogenated conjugated diene polymer having a number average molecular weight of about 10,000 -300,000 and terminal blocks of an aromatic vinyl polymer having a number average molecular weight of about 5,000 - 125,000, the intermediate blocks of said block copolymers being at least 95%
hydrogenated, wherein the total of said first block copolymer and said second block copolymer is equal to 100 parts by weight.
2. The resin composition of Claim 1 in which the hydrogenated conjugated diene polymer is a hydrogenated polybutadiene or polyisoprene.
3. The resin composition of Claim 1 in which the aromatic vinyl polymer is polystyrene, poly-.alpha.-methylstyrene or poly-p-methylstyrene.
4. The resin composition of Claim 1 containing 25 to 80 parts by weight of the first block copolymer and 75 to 20 parts by weight of the second block copolymer.
5. The resin composition of Claim 1 which is molded or extruded to form a sheet or tube.
CA000538842A 1987-06-04 1987-06-04 Moldable block copolymer resin composition Expired - Fee Related CA1300776C (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CA000538842A CA1300776C (en) 1987-06-04 1987-06-04 Moldable block copolymer resin composition

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CA000538842A CA1300776C (en) 1987-06-04 1987-06-04 Moldable block copolymer resin composition

Publications (1)

Publication Number Publication Date
CA1300776C true CA1300776C (en) 1992-05-12

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Family Applications (1)

Application Number Title Priority Date Filing Date
CA000538842A Expired - Fee Related CA1300776C (en) 1987-06-04 1987-06-04 Moldable block copolymer resin composition

Country Status (1)

Country Link
CA (1) CA1300776C (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112689554A (en) * 2018-09-14 2021-04-20 Agc株式会社 Method for producing pellet, and ion exchange membrane

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112689554A (en) * 2018-09-14 2021-04-20 Agc株式会社 Method for producing pellet, and ion exchange membrane
CN112689554B (en) * 2018-09-14 2023-05-16 Agc株式会社 Process for producing pellet, and ion exchange membrane

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