阅读说明：本技术 高柔软性，不粘和透明的苯乙烯热塑性弹性体组合物 (High-softness, non-stick and transparent styrene thermoplastic elastomer composition ) 是由 M·沃斯万微尔 N·尼斯内 E·扬克 D·瓦格纳 K·克诺尔 于 2018-03-12 设计创作，主要内容包括：可用于医疗应用的热塑性弹性体组合物,其包括：a)90.9至69.0重量％的星形嵌段共聚物[S<Sub>1</Sub>-(S/B)<Sub>k</Sub>-(S/B)<Sub>l</Sub>-(S/B)<Sub>m</Sub>-S<Sub>2</Sub>]<Sub>n</Sub>-X,其中S<Sub>1</Sub>和S<Sub>2</Sub>为乙烯基芳族硬聚合物,S/B为无规乙烯基芳族/二烯软共聚物嵌段；X是耦合中心；和b1)矿物油B1和环己烷1,2-二羧酸C8-C10二烷基酯B2的混合物；或者b2)矿物油B1和植物油B3的混合物。(A thermoplastic elastomer composition useful for medical applications comprising: a)90.9 to 69.0% by weight of starsBlock copolymer [ S ] in shape 1 ‑(S/B) k ‑(S/B) l ‑(S/B) m ‑S 2 ] n -X, wherein S 1 And S 2 Is a vinyl aromatic hard polymer and S/B is a random vinyl aromatic/diene soft copolymer block; x is a coupling center; and B1) a mixture of mineral oil B1 and C8-C10 dialkyl cyclohexane1, 2-dicarboxylate B2; or B2) a mixture of mineral oil B1 and vegetable oil B3.)

1. A thermoplastic elastomer composition comprising components a), b) and c):

a) from 90.9 to 69.0% by weight of at least one radial block copolymer A of the structure

[S₁-(S/B)_k-(S/B)_l-(S/B)_m-S₂]_n-X (I)，

Wherein S₁And S₂Is a polymer block made of a vinyl aromatic monomer, S/B is a random copolymer block made of at least one vinyl aromatic monomer and at least one diene as a soft phase; x is a coupling center derived from a multifunctional coupling agent;

b)9.1 to 31.0 wt% of plasticizer B; and

c)0 to 2.0 wt.% of other additives C;

wherein the sum of components a), b) and c) is 100% by weight;

each arm S₁-(S/B)_k-(S/B)_l-(S/B)_m-S₂Are all the same;

based on all block copolymers A, S₁And S₂The proportion of the (hard phase forming) is 24 to 40% by weight.

The ratio of vinylaromatic monomer/diene (i.e. S/B) in all blocks (S/B) is from 1/0.45 to 1/2.5;

block (S/B)_k,(S/B)_lAnd (S/B)_mAre different from each other; block (S/B)_kAnd (S/B)_mWith a lower S/B ratio than block (S/B)_lThe S/B ratio of (1);

block S₂/S₁In a weight ratio of 0.1 to 0.8; and

weight average molar mass M of Block copolymer A_w(determined by GPC according to ISO 16014-3: 2012) from 200,000 to 450,000 g/mol; n is a natural number from 1 to 8; k and m are 1; l is a natural number of at least 1; and plasticizer B is

b1) From mineral oil B1 and at least one cyclohexane-1, 2-dicarboxylic acid C₈-C₁₀Mixtures of dialkyl esters B2; or

b2) A mixture consisting of mineral oil B1 and at least one vegetable oil B3 having an iodine value (g/100g) of not more than 130.

2. The thermoplastic elastomer composition according to claim 1, wherein the weight ratio of component B1 to component B2 or B1 to B3 in the plasticizer in plasticizer mixture B1) or B2) is from 80:20 to 40: 60.

3. The thermoplastic elastomer composition according to claim 1 or 2, wherein the plasticizer B is a mixture B2).

4. Thermoplastic elastomer composition according to any one of claims 1 to 3, wherein the vegetable oil B3 is selected from the group consisting of: rapeseed oil, sunflower oil, grape seed oil, palm oil, olive oil, coconut oil, palm kernel oil, cocoa butter, jojoba oil, cottonseed oil, corn oil, wheat germ oil, soybean oil, peanut oil, castor oil, sesame oil and rice oil; rapeseed oil is preferred.

5. The thermoplastic elastomer composition according to any one of claims 1 to 4, wherein the vegetable oil B3 is rapeseed oil.

6. Thermoplastic elastomer composition according to any one of claims 1 to 5, having a melt mass flow index (measured with a polymer melt at 200 ℃ and 5kg load according to ISO 1133-1: 2011) in the range of from 8 to 16cm³10 minutes, preferably 9 to 15cm³10 minutes.

7. Thermoplastic elastomer composition according to any one of claims 1 to 6, comprising 9.1 to 20.0 wt.%, more preferably 13.0 to 20.0 wt.% of plasticizer B (component B)), and M of block copolymer A_w250000 and 320000 g/mol.

8. Thermoplastic elastomer composition according to any one of claims 1 to 6, comprising more than 20% by weight, in particular 21 to 31.0% by weight, of plasticizer B (component B)), and M of block copolymer A_w325000-

9. The thermoplastic elastomer composition according to any one of claims 1 to 8, wherein n is a natural number of 3 to 5.

10. The thermoplastic elastomer composition according to any one of claims 1 to 9, wherein

X is a coupling center derived from epoxidized linseed oil or epoxidized soybean oil.

11. Thermoplastic elastomer composition according to any one of claims 1 to 10, wherein the polymer block S₁M of (A)_wIs 22900 to 54000g/mol, preferably 25600 to 42660g/mol, and a polymer block S₂M of (A)_wIs from 5000 to 12000g/mol, preferably from 5000 to 12000g/mol, more preferably from 5700 to 9500 g/mol.

12. According to any one of claims 1 to 11Thermoplastic elastomer composition, wherein the block S of the block copolymer A₂/S₁Is 0.1 to 0.6, preferably 0.15 to 0.40, more preferably 0.15 to 0.3.

13. The thermoplastic elastomer composition according to any one of claims 1 to 12, wherein the copolymer block (S/B)_kIs 0.5 to 1.0, preferably 0.65 to 0.85; copolymer block (S/B)_lHas an S/B ratio of 0.5 to 1.2, preferably 0.7 to 1.1, and a copolymer block (S/B)_mIs 0.3 to 0.8, preferably 0.40 to 0.70.

14. The thermoplastic elastomer composition according to any one of claims 1 to 13, wherein the copolymer block (S/B)_k,(S/B)_lAnd (S/B)_mWeight average molar mass M of_wAre different from each other. (S/B)_kM of (A)_w16500 to 40000 g/mol; (S/B)_lM of (A)_w25800 to 60800 g/mol; (S/B)_mM of (A)_wFrom 14300 to 33800 g/mol.

15. A process for preparing a thermoplastic elastomer composition according to any one of claims 1 to 14, wherein component a) is introduced continuously into an extruder and component b) and optionally further component c) are metered in.

16. A process for the preparation of a thermoplastic elastomer composition according to any one of claims 1 to 14, wherein component b) and optionally component c) are added directly or in solution to a solution of block copolymer a, the liquid is then homogenized and the solvent is removed from the product.

17. A shaped article, in particular a medical article, produced from the thermoplastic elastomer composition of claims 1 to 14.

18. Use of the thermoplastic elastomer composition according to any one of claims 1 to 14 in medical applications, in particular skin-contacting applications, such as mouthpieces and diapers, and intravenous applications, such as bags and tubes.

19. A radial block copolymer a according to any one of claims 1 and 9 to 14.

20. A process for preparing block copolymers A of the formula (I) according to any of claims 1 and 9 to 14,

i) the single-time initiation is carried out,

ii) first adding and polymerizing a vinylaromatic monomer,

iii) carrying out at least 3 times the addition and polymerization of the mixture of vinylaromatic monomer and diene,

iv) a second addition and polymerization of a vinylaromatic monomer, and

v) a coupling step, which is carried out after addition and polymerization of the vinylaromatic monomer to form the final polymer block.

Description of the invention

The present invention relates to styrenic thermoplastic elastomers (S-TPEs), to soft thermoplastic elastomer compositions comprising said S-TPEs, to the production of flexible or elastic moulded articles, and further to the use of said moulded articles, in particular for medical applications.

Conventional thermoplastic elastomers used in medical applications, such as plasticized PVC, have several disadvantages. PVC is a relatively polar polymer and therefore requires a relatively polar plasticiser (e.g. a phthalate). When medical hoses made of PVC are joined together with parts made of rigid styrene polymers, migration of plasticizers from the PVC part to the styrene part often occurs. This migration destroys plasticity and reduces environmental stress cracking resistance. Therefore, for medical applications, it is necessary to avoid the use of typical PVC plasticizers. Particularly for skin-contacting medical applications, there is a need for improved thermoplastic elastomeric materials that can employ food grade plasticizers so as not to interfere with human hormonal regulation.

Patents US 6,031,053 and US 6,197,889 disclose elastomeric linear and star SBC block copolymers of the general formula Y- [ (a-B/a)_n-A]_m+1And Y- [ (B/A-A)_n]_m+1Wherein A is a hard phase formed by a vinyl aromatic block, B/A is a random diene/vinyl-aromatic copolymer block forming a soft phase, Y is a group of a coupling agent, and m and n are 1 to 10. Examples of which show coupled star-block copolymersThe polymer has a structure of Y- [ (B/A) - (B/A) - (B/A) -A]The molecular weight Mw was 175000g/mol or 145000 g/mol.

WO 2012/055919 describes star elastomeric SBC block copolymers having at least two different arms and mixtures thereof. Preferred are coupled block copolymers having 3 or 4 arms, with a hard-soft-hard pentablock character of the formula [ A1-B/A-A2-]_m[A2-]_lY, wherein A1 and A2 are vinyl aromatic hard blocks (A1 is greater than A2) and B/A are vinyl aromatic/diene copolymer soft blocks. For many applications, the above elastomeric SBC block copolymers are too stiff. In order to reduce the hardness, it has been proposed to use plasticizer oils which are more polar than medical white oils but less polar than the common PVC plasticizers.

US 6,673,857 discloses a thermoplastic elastomer composition comprising 5 to 99 wt% of an SBC block copolymer and 1 to 95 wt%, preferably 4 to 49 wt% of a plasticizer based on a vegetable oil or a mixture thereof with a white oil. The SBC block copolymer is a symmetric triblock copolymer or a star block copolymer, containing an outer block S and a middle random soft block B/S (no examples). Having a linear S-B/S-S block copolymer (Mw 163000g/mol) and 5 or 10% by weight of a mixture of white oil/sunflower oil (40/60), a Shore A hardness of 68 or 63, a high melt flowability of 16.9 or 27.8(5kg, 10 min.) at 180 DEG C¹)。

These thermoplastic elastomer compositions still have some points to be improved in terms of their processability. Furthermore, there is a need to improve their flexibility without bleeding out plasticizer oil.

WO 2012/084914 describes thermoplastic elastomer compositions comprising a) 5% to 99% by weight of a block copolymer synthesized from hard blocks a of vinyl aromatic monomers and one or more random soft blocks B of diene/vinyl aromatic copolymers, and B) 1% to 95% by weight of a plasticizer, in particular a mixture of diisononylcyclohexane-1, 2-Dicarboxylate (DINCH) with white oil. The block copolymer is preferably a symmetric triblock copolymer comprising an outer block a and an inner block B. With the plasticizer combination, it is possible to increase the oil absorption of the triblock copolymer to 50% by weight and improve the softness, but the mechanical properties of this material are not satisfactory for many applications.

There is therefore a need for an improved material which is suitable for medical applications and which does not have the above-mentioned disadvantages.

Example (b):

and (3) a plasticizer B:

B1 70, a commercially available medical white oil

B2 produced by BASF SE, Germany(DINCH)

Rapeseed oil produced by B3 Cargill AP-60

Block copolymer A1

A star block copolymer A having the structure [ S₁-(S/B)_k-(S/B)_l-(S/B)_m-S₂]_nPreparation of-X, by sequential anionic polymerization of styrene (monomers S1 to S5) and butadiene (monomers B1 to B3) (see table 1), followed by coupling using epoxidized soybean oil. 25670ml of cyclohexane were used as initial charge (ic), titrated to the end with 1.6ml of sec-butyllithium (BuLi ic), cooled to 45 ℃ and 1.4M of a solution of sec-butyllithium was added as initiator in the amounts indicated in Table 2 and 0.3304M of a solution of potassium tert-amylate (PTA) as randomizer in the amounts indicated in Table 2. Next, the initiator mixture was then mixed and cooled to 40 ℃. In the next step, 1350 g of styrene were added (S1) and the polymerization was carried out until the monomers were completely consumed (determined by the decrease in the temperature of the reaction mixture). In the next step, 570 g of butadiene (B1) and 415 g of styrene (S2) were added simultaneously to the polymerization and the polymerization was allowed to proceed until the monomers were completely consumed (determined by the decrease in the temperature of the reaction mixture).

In the next step, 800g of butadiene (B2) and 720 g of styrene (S3) were again added simultaneously to the polymerization and the polymerization was allowed to proceed until complete consumption of the monomers (determined by the decrease in the temperature of the reaction mixture). In the next step, 535 g of butadiene (B3) and 310 g of styrene (S4) were again added simultaneously to the polymerization and the polymerization was allowed to proceed until complete consumption of the monomers (determined by the decrease in the temperature of the reaction mixture). In the next step, 300 g of styrene were added (S5) and the polymerization was allowed to proceed until complete consumption of the monomer (determined by the decrease in temperature of the reaction mixture).

Finally, 10mL of cyclohexane in the amounts indicated in Table 2 were added at a temperature between 45 and 55 deg.CD82 was used as a coupling agent and allowed to react for 10 minutes. Finally, 5ml of isopropanol are added and the mixture is filteredStirred for 10 minutes. Next, the mixture was stirred with 10mL of distilled water and 5 minutes of CO₂The gas stream (0.1kg/h) was acidified. Finally, 0.135 wt% phm Irganox 1010, 0.180 wt% phm Irgaphos 168 and 0.135 wt% phm Sumilizer GS were added.

Phm ═ per 100 parts by weight of monomer (% by weight of the components calculated as the total mass of the monomers for the initiator, coupling agent, etc.)

Table 1: block copolymer A (composition and order of addition)

By using the appropriate amounts of BuLi, PTA and Edenol (see Table 2), different weight-average molar masses M were obtained according to the preparation method described above (see Table 1)_wBlock copolymers a1 to A8.

Table 2 further shows the measured Shore A hardness of S-TPE compositions comprising one of the block copolymers A1 to A8 and varying amounts of plasticizer B (the B1/B2 or B1/B3 ratio in plasticizer B being the highest amount at which bleeding does not occur, see Table 4).

TABLE 2

Block copolymer C1 (comparative Compound)

Has a structure S₁-(B₁/S₂)-(B₂/S₃)-(B₃/S₄)-S₅(see Table 3) the linear block copolymer C1 was prepared by sequential anionic polymerization of styrene (monomers S1 to S5) and butadiene (monomers B1 to B3), the polymerization reaction being terminated with 15mL of isopropanol. The linear block copolymer C1 was prepared in a similar manner to block copolymer a described above, except for the coupling step. Further, 17970mL of cyclohexane were used as solvent, in each case the end blocks S were made from 960g of styrene, random soft blocks (B)₁/S₂) Made of a mixture of 660g of styrene and 700g of butadiene, random soft block (B)₂/S₃) Made of a mixture of 852g of styrene and 904g of butadiene, and random soft block (B)₃/S₄) Made from a mixture of 468g of styrene and 496g of butadiene. 37.59mL of a 1.4M solution of sec-butyllithium and 4.49mL of a 0.304M solution of potassium tert-amylate (PTA) were used to initiate the polymerization. After the polymerization was terminated, the mixture was stirred with 10mL of distilled water and 5 minutes of CO₂The gas stream (0.1kg/h) was acidified. Finally, 12g Irganox 1010, 16.2g Irgaphos 168 and 12g Sumilizer GS were added.

Molecular weight: 141930 g/mol

Shore a (ASTM D2240(15 sec)): 84

Table 3: block copolymer C (composition and order of addition)

Preparation of S-TPE compositions

In a stirred vessel, a cyclohexane solution of one of the resulting stabilized block copolymers a1 to A8 or block copolymer C1 (polymer content 27.8 wt.%), further 0 to 45phm of plasticizer B (based on 100 parts by weight (phm)) of the total amount of monomers required for the synthesis of block copolymer a) was added and mixed homogeneously at 60 ℃. The solution was then degassed to give S-TPE compositions for further testing (see tables 2, 4 and 5).

Seepage and overflow test

Samples with different plasticizer concentrations and plasticizer compositions (see table 4) were pressed into boards and then cut into sheets (3cmx3 cm). Next, the sample was stored on absorbent paper (adsorption paper) under a 5kg load at 35 ℃. After one week, the bleed-over of plasticizer B to the absorbent paper (sheeting) was evaluated according to the following scale:

no seepage overflow (no stickiness)

1 ═ absorption paper with exudation spots

2-there are bleeding spots on the absorbent paper + the polymer sample is greasy

Table 4 shows that S-TPE compositions of the invention containing block copolymer A (see samples 27 and 28 of the invention having a total plasticizer B concentration of 40 phm) increase the oil absorption without bleed. Even at a total oil concentration of 45phm, a percolation fraction of 0 can be achieved.

TABLE 4

Total concentration of plasticizer B (phm) based on total weight of monomers of block copolymer A or C

Mechanical Properties

Samples with different plasticizer concentrations and plasticizer compositions were pressed at 200 ℃ into 2mm thick plates. Next, tensile test bars were pneumatically extruded from the die plate material (1 cm from the edge) according to ISO 527-1A and tempered (tempered) for 24 hours at 23 ℃. Finally, the test bars were subjected to tensile testing on a Zwick tensile tester (2.5kN +500N) according to the ISO 527 procedure.

The measured E modulus, breaking stress and breaking strain are shown in table 5.

TABLE 5

Total concentration of plasticizer B (phm) based on total weight of monomers of block copolymer A or C

Table 5 shows that the S-TPE compositions of the invention have significantly improved mechanical properties, together with very good flexibility, as indicated by their Shore A hardness (see Table 2), almost all values being between 60 and 40.

Very good overall results, including their mechanical properties, were obtained with compositions containing the plasticizer mixture B1/B3. S-TPE compositions comprising from 15 to 20phm of plasticizer B, in particular plasticizer B2) (blend B1/B3) exhibit high stress at break (greater than 11MPa) and are very soft (Shore A hardness from 64 to 50).

Compositions comprising 30-45phm of plasticizer B, in particular plasticizer B2) (mixture B1/B3) show good stress at break (typically greater than 8MPa) and high strain at break (typically greater than 1200%) and are very soft (shore a hardness of 45 to 38).

Optical properties and melt volume flow rate

Samples were prepared as described above and tested for optical properties. In addition, the MFI (200 ℃, 5kg) of these samples was determined.

Clarity, Haze and clarity (clarity) were measured on 2mm compression molded plaques according to ASTM D1003 using BYK Haze-gard I. The molded plates were produced at 200 ℃ under 40bar for 10 minutes. Table 6 shows the data obtained.

TABLE 6

The data shown in table 6 demonstrate that the compositions of the invention have high transparency and that the MFI values of the obtained inventive samples show good processability even with increased amounts (e.g. 40, 45phm) of plasticizer.