FI101391B - Polar copolymer mixture - Google Patents

Description

101391

The invention relates to a polar polymer composition which is particularly well suited for the production of various non-hammered hoses.

Stuttering is a well-known problem in many hose applications. The hose is said to squirm when, when bent, it suddenly collapses (squats) 10 so that the flow inside the hose is considerably reduced or completely blocked. Such a situation in medical applications can be very dangerous, because then the solution entering the patient or the secretion leaving the patient cannot travel forward.

Non-hammered tubing for medical applications is made primarily of 15 plasticized polyvinyl chloride (PVC). The PVC hose can be bent to a very sharp bend without reducing the flow. Today, however, there is a requirement to restrict the use of PVC, especially in medical and food applications. PVC is also considered a cumbersome material for environmental reasons. On the other hand, for example, when administering drugs, the drugs may be absorbed on the surface of the PVC and the administration may not be uniform.

Undamaged hoses are also made of other materials with structural: · 'solutions. In this case, nested structures, layered structures or so-called corrugated • · · • «* · · 'hoses with an accordion-like part at regular intervals have been used. Making such hoses is expensive • · »25 and cumbersome and usually requires special equipment. Such a corrugated hose is disclosed in, for example, U.S. Patent 4,000,341.

• · · • · · .. Little use has been made of polyolefin materials for undamaged hoses. Some • · · polyolefins are suitable for the manufacture of hoses, but they are easily hammered.

PCT patent application WO92 / 18173 discloses the replacement of PVC with very low density polyethylene (PE-VLD) with a density of 0.880-0.900 and a melt index »• · ·

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2 101391 1-12. A hose made of ordinary low density polyethylene (PE-LD) is very easily bent.

U.S. Patent 3,865,776 discloses a non-abrasive tubing for medical applications made from a complex polymer blend containing two types of block copolymer, high melt index polypropylene and additional white oil and resin.

In SE 422328, the problem is solved by using two different polar copolymers of ethylene with different melt indices. Both polymers are ethylene / vinyl acetate copolymers (E / VA). According to the publication, the properties are improved by using two instead of one E / VA polymer.

Another publication SE 336 226 uses small amounts of a high melt index E / VA 15 copolymer blended with an ethylene / ethyl acrylate copolymer (E / EA). The polymer blend is intended for cable sheaths.

The object of the present invention was to provide a simple polymer blend, the tubes of which are non-abrasive and suitable for both medical and:. 20 for other applications.

«« · • · • · •; '; Blending of two polar copolymers of ethylene, one with a low • · · · ··· melt index, MFR <10, and the other with a very high melt index, MFR> 100, results in a • · · · polymer blend from which the hoses are undamaged and also from other 25 good properties. Copolymers of ethylene and hydroxy (meth) acrylates are used as the low melt index polymer and as the high melt index copolymer is an ethylene / vinyl acetate copolymer with a really high melt index, i.e. more than 100.

In this case, it really softens the material, but when the other component is rigid, the end result is an uncomplicated, flexible, yet sturdy hose.

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1-50% by weight of a high melt index copolymer and 99-50% by weight of a low melt index copolymer can be used in the polymer mixture according to the invention. The amount of high melt index polymer cannot be more than 50% by weight, because then the mixture can no longer be properly processed.

5 It seems obvious that a polymer with a high melt index works in the same way as a plasticizer when using polyvinyl chloride.

The low melt index polymer is an ethylene / hydroxy (meth) acrylate polymer having 5-30% by weight of hydroxyalkyl (meth) acrylate as one comonomer and 0-40% by weight of vinyl acetate as the other comonomer. The polymer having a high melt index is preferably an ethylene / vinyl acetate copolymer having a vinyl acetate content of 1 to 40% by weight.

In the ethylene / hydroxy (meth) acrylate polymer of the composition of the invention, the hydroxy (meth) acrylate may be any ester of glycol or polyglycol and acrylic or methacrylic acid, but in most cases hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate or hydroxypropyl acrylate are suitable. The hydroxy (meth) acrylate content of the copolymer is at most 30% by weight. In addition to the hydroxy (meth) acrylate, the polymer may contain 0-40% by weight of other comonomers such as vinyl acetate, acrylic acid, methacrylic acid or esters thereof.

• · · "V The use of an ethylene / hydroxy (meth) acrylate polymer in a polymer blend for hoses. other polyolefins.

• · • · · • ·. *. The polymer blend is prepared by conventional polymer blend preparation methods, such as, <· «. by melt mixing in a 1- or 2-screw extruder or Banbury mixer. Also <«. *. 30 dry mixes can be used.

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The polymer blends may also contain small amounts of conventional polymeric additives such as antioxidants, anti-adherents or anti-fogging agents, anti-static agents, and the like.

The invention is further illustrated by the following example:

Example 1

The following materials were used in the experiments: 10 NCPE 5428 = ethylene / vinyl acetate copolymer (E / VA), manufactured by Borealis Polymers Oy, melt index MFR = 400, vinyl acetate content 28% NCPE 0467 = ethylene / hydroxyethyl methacrylate / vinyl acetate / EP; Polymers Oy, melt index MFR = 1, total comonomer content 19% NCPE 2410 = low density polyethylene (PE-LD), manufacturer Borealis Polymers Oy, melt index MFR = 1.

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Polymer blends were prepared by the so-called dry blending. A thin hose was made from the mixtures by a conventional extrusion method: inner diameter 5.8 mm and outer diameter 7.4 mm. Extrusion temperatures were 120-160 ° C.

»·» • · »• t» · • 111 ^ 25 The hose made of finished polymer blends was flexible and bent by hand without bending into a loop with a diameter of less than 200 mm. Thus, the flow of liquid in the hose was possible all the time. 200 mm was used as the loop diameter in the experiments because • · ·. ·: ·. it is a commonly used requirement for tubing for medical applications.

'' .1 .. '30 Hoses were made from the polymer blends shown in Table 1. A polyethylene hose was made as a control. It was flexible but bent when bent.

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Table 1. Polymer blends used

Test 1 Test 2 Test 3 Test 4 Test 5 Comparative Test NCPE 5428 5 10 20 30 40 5 NCPE 0467 95 90 80 70 60 NCPE 2410 ----- 100 bending yes yes yes yes yes no without hesitation 10 1 «·» t • · · • «• · • ·«

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Claims (5)

6 101391 Polymer blend suitable for the production of ham-free hoses, characterized in that it contains 5 (A) 99-50% by weight of ethylene / hydroxy (meth) acrylate copolymer or terpolymer, in which 5-30% by weight of hydroxyalkyl (meth) acrylate and as a second comonomer 0-40% by weight of a vinyl compound having a melt index of less than 10 and (B) 1-50% by weight of an ethylene / vinyl acetate copolymer having a vinyl acetate content of 1-40% by weight and a melt index of at least 100. Polymer mixture according to Claim 1, characterized in that the vinyl compound of the polymer (A) is vinyl acetate. Polymer mixture according to Claims 1 or 2, characterized in that the hydroxyalkyl (meth) acrylate is hydroxyethyl methacrylate or hydroxypropyl methacrylate. 4. A polymer blend suitable for the production of undamaged hoses, characterized in that it contains I 1 I i 20 (A) 99-50% by weight of ethylene / hydroxyethyl methacrylate / vinyl acetate terpolymer ii I: '(E / VA / HEMA), in which the comonomer content is a total of 10 to 25% by weight and has a melt index of less than 5, and (·) 1 to 50% by weight of an ethylene / vinyl acetate copolymer (E / VA) having a vinyl acetate content of 10-30% by weight and with a melt index of 300 or more. • · · 25 • · «• · · A hose made according to any one of the preceding claims. polymer blend. • ·: ···: 30 7 101391 Paten tkrav: