KR20020047281A - Blended Polycarbonate Compositions - Google Patents

Abstract

The present invention relates to light diffusing polymer compositions comprising polycycloolefins such as hydrogenated polystyrene, polystyrene copolymers and polycarbonates mixed with cycloolefin (co) polymers.

Description

Blended Polycarbonate Compositions

Light diffusing polymers are mainly used as materials for lighting and sunroofs, in particular for industrial building materials. These polymers diffuse light somewhat regularly in all directions. In addition, the translucent loops made of polycarbonate protect from the daylight and prevent the typical disadvantages of toughened glass (difficult to cut) [DE-A-44 37 312, DE-A-22 51 708].

Light diffusing materials are also successfully used in projection systems by hiding scratches and defects in rear projection screens, such as television screens or laminate electrical decorative films (US 5 170 287).

Other possible uses of the light diffusing polymer include lighting devices, light signs, in particular back light signs of milky light, upright lights, automotive sunroofs, covers for automotive lights and the like.

Light diffusion in originally transparent polycarbonates is achieved by adding a light diffusing agent to the polymer. Excellent milky polycarbonate filled with inorganic additives or pigments (BaSO ₄ and TiO ₂ particles are often used for this purpose, ZnO, ZnS, CdS, CaCO ₃ are also used) or poly (meth) acrylate based spherical particles It shows photogenicity.

Unfortunately, in such systems, problems may arise regarding the relationship between transparency and haze, mechanical properties and stability. White pigments, such as TiO ₂ , ZnO, ZnS, reduce the transmittance of light, greatly limiting their use as lighting materials. Decreasing the pigment concentration results in no substantial diffusion and leaves the material transparent (DE-A-20 19 325).

Another serious problem is the reduced molecular weight of the inorganic fillers, in particular polycarbonate samples filled with TiO ₂ . This degradation was observed to depend on the type and concentration of filler. It is believed that inorganic pigments are involved in the decomposition reactions that occur during processing (eg injection molding), especially when small amounts of water (eg, as moisture in the air) are present in the polymer. Reduction in molecular weight can negatively affect the mechanical and other properties of the polymer. When 1.5% by weight of TiO ₂ in the polycarbonate matrix is used, 0.15 to 0.2% by weight of water in the polycarbonate is sufficient to cause decomposition of the matrix (DE-A-20 19 325).

Inorganic particles tend to wear processing equipment because they are difficult to evenly distribute in the matrix, and are hard and irregularly ground. In addition, the surface of the polycarbonate article comprising such particles is uneven. Holes and holes may be observed due to the large particle size of BaSO ₄ (EP-A-269 324 and EP-A-634 446).

Some of the above problems (particularly matrix decomposition, rough surfaces, etc.) can be overcome by replacing inorganic light diffusing agents with organic particles made of other polymers. Some polyalkyl methacrylates and polyalkyl acrylates are mainly used. The advantage of opalescent polycarbonates with organic light diffusing agents is that they reduce the total concentration of the additive by five times. However, in such a system, there is no strong adhesion between the two phases of the matrix and the particles, resulting in poor physical strength and dispersibility of the matrix and the particles (US 5 237 004 and EP-A-269 324). Another drawback of polyalkyl methacrylate and polyalkyl acrylate based particles for opalescent polycarbonate is the need to use a certain amount of TiO ₂ , which makes the use of the inorganic pigment in question practically inevitable. will be. Polyalkyl (meth) acrylate particles have low thermal stability and greatly limit their use in lighting devices.

The present invention relates to a light diffusing polymer composition comprising a polycarbonate blended with a polycycloolefin such as hydrogenated polystyrene, hydrogenated styrene polymer, hydrogenated cycloolefin (co) polymer.

In order to avoid the above problems of coarse and unevenly dispersed inorganic particles, a low content of polycycloolefin, preferably hydrogenated polycycloolefin, in particular hydrogenated polystyrene, has been used to impart opioidity to polycarbonates. . These hydrogenated polycycloolefins create separate phase regions in the polycarbonate matrix, which diffuse light. The strong diffusion of these polymeric regions in polycarbonates can be explained by the significant difference between polycycloolefin and polycarbonate refractive indices.

Scheme I shows the repeating units of the preferred polycycloolefins represented in the present invention such as hydrogenated polyvinylcyclohexane (HPS), Apel (Apel®) and arton (Arton®). Hydrogenated polyvinylcyclohexane can be synthesized by catalytic hydrogenation of polystyrene (Examples 1 to 3), and Arton® and Apel® are Japan Synthetic Rubber and It is marketed by Mitsui Corp.

Scheme I

Milky white polycarbonate is usually prepared by combining standard polycarbonate with a light-diffusing inorganic compound such as BaSO ₄ to produce a masterbatch, and then further mixing with polycarbonate according to consumer requirements. do. Using the polymeric light diffusing agent according to the invention, it is possible to produce the final product in a single step without the use of pre-made polycarbonate blends (masterbatches) to reduce the production costs.

The opalescent polycarbonate blends and / or polycarbonate products according to the invention are prepared by mixing or blending polycarbonates and polycarbonates hydrogenated in conventional methods, preferably in kneaders or extruders. . It is preferable to produce the opalescent polycarbonate twin-wall sheet by coextrusion when a UV protective layer (10-200 μm thick, preferably 60 μm thick) covering the bilayer sheet is produced.

It is preferred to incorporate up to 25% by weight of polycycloolefin, preferably 0.01 to 10% by weight, in particular 0.1 to 6% by weight, in the polycarbonate.

The basic properties of the blends according to the invention or products made from these blends, such as haze and total transmission, are shown in Table I. As shown in this table, even a small amount of hydrogenated polycycloolefin can achieve virtually complete light diffusion in the polycarbonate composition, where the total transmittance is maintained at 23 to 40% (in the wavelength range of 450 to 700 nm). do. The relationship between haze and transmittance can be easily and precisely adjusted by varying the content of the light diffusing polymer additive. The haze of polystyrene (PS) is substantially lower than its hydrogenated analog.

In addition, incorporation of this amount of polycycloolefin does not impair the mechanical properties of the polycarbonate or polycarbonate product.

In order to cause light diffusion in the polycarbonate, in addition to HPS, Arton® and Apel®, other polyolefins as described in Canadian Patent Application No. 2 134 320 may be preferably used: poly Cyclobutene, polycyclopentene, polycyclohexene, 3,4-dimethylcyclopentene, 3-methylcyclohexene, 2- (2-methylbutyl) -1-cyclohexene, cyclooctene, polynorbornene (preferably Prepared by polymerizing 2-norbornene), 5-methyl-2-norbornene, 5-ethyl-2-norbornene, 5-isopropyl-2-norbornene, 5-n-butyl-2 -Norbornene, 5-isobutyl-2-norbornene, 5,6-dimethyl-2-norbornene, 5-chloro-2-norbornene, 5-fluoro-2-norbornene, 5 -Vinyl-2-norbornene, 5-ethylidene-2-norbornene, bicyclo [2.2.1] -2-heptene and derivatives thereof, tetracyclo [4.4.0.1 ^2.5 .1 ^7.10 ] -3-dode Sen and its derivatives, hexacycles ^{[6.6.1.1 3.6 1 10.13 .0 2.7 .0} 9.14] -4- hepta-decene and, octanoyl cycloalkyl derivatives thereof ^{[8.8.0.1 2.9 .1 4.7 .1 11.18 .1} 13.16 .0 3.8 .0 12.17] -5- Toko Sen and its derivatives, pentacyclo [6.6.1.1 ^3.6 .0 ^2.7 .0 ^9.14 ] -4-hexadecene and its derivatives, heptacyclo [8.7.0.1 ^2.9 .1 ^4.7 .1 ^11.17 .0 ^3.8 .0 ^12.16 ] -5 Eicosene and its derivatives, heptacyclo [8.8.0.1 ^2.9 .1 ^4.7 .1 ^11.17 .0 ^3.8 .0 ^12.16 ] -5-heneicosene and its derivatives, tricyclo [4.3.0.1 ^2.5 ] -3-decene and Derivatives thereof, tricyclo [4.4.0.1 ^2.5 ] -3-undecene and derivatives thereof, pentacyclo [6.5.1.1 ^3.6 .0 ^2.7 .0 ^9.13 ] -4-pentadecene and derivatives thereof, pentacyclo [6.5.1.1 ^3.6 .0 ^2.7 .0 ^9.13 ] -4,10-pentadecadiene and derivatives thereof, heptacyclo [8.7.0.1 ^3.6 .1 ^10.17 .1 ^12.15 .0 ^2.7 .0 ^11.16 ] -4-Eicocene and derivatives thereof as well as other Cycloaliphatic monomers.

Polycarbonates used in the blending or blending with polymeric light diffusing agents can be prepared by phosgenation processes or melt polymerization. As for the melt volume flow rate (ISO 1133, 300 degreeC, 10 minutes) of polycarbonate, 3-8 cm <3> / (10 minutes) is preferable, and 6cm <3> / (10 minutes) is more preferable.

The following aromatic and aliphatic diols are shown as such polycarbonates: 2,2-bis (4-hydroxyphenyl) propane (bisphenol A), 2,2-bis (4-hydroxyphenyl) perfluoropropane , 1,1-bis (4-hydroxyphenyl) cyclohexane, 1,1-bis (4-hydroxyphenyl) -3,5,5-trimethylcyclohexane (TMC bisphenol), 4,4 '-(1 , 3-phenylenediisopropylidene) bisphenol, 4,4'-dihydroxybiphenyl, 4,4 '-(1,4-phenylenediisopropylidene) bisphenol, 4,4'-dihydroxydiphenyl Sulfide, 1,1-bis (4-hydroxyphenyl) ethane, 4,4'-dihydroxydiphenyl, 2,4- (dihydroxyphenyl) -2-methylbutane, α, α'-bis (4-hydroxyphenyl) -p-diisopropylbenzene, 2,2-bis (3-methyl-4-hydroxyphenyl) propane, 2,2-bis (3-chloro-4-hydroxyphenyl) propane , Bis (3,5-dimethyl-4-hydroxyphenyl) methane, 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane, bis (3,5-dimethyl-4-hydroxyphenyl ) Sulfone, 2,4-bis (3,5-di Methyl-4-hydroxyphenyl) -2-methylbutane, 1,1-bis (3,5-dimethyl-4-hydroxyphenyl) cyclohexane, α, α'-bis (3,5-dimethyl-4- Hydroxyphenyl) -p-diisopropylbenzene, 2,2-bis (3,5-dichloro-4-hydroxyphenyl) propane, 2,2-bis (3,5-dibromo-4-hydroxy Phenyl) propane, 4,4'-dihydroxydiphenyl sulfone, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 1,5-dihydroxynaphthalene, 1,6-dihydroxy Naphthalene, 4,4'-dihydroxybenzophenone, 2,2 ', 6,6'-tetrabromo-2,2-bis (4-hydroxyphenyl) propane, bis (4-hydroxyphenyl) alkane (1 to 25 carbon atoms in the alkali chain), 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxy-3,3'-dimethyldiphenyl ether, ethylene glycol bis (4-hydrate Hydroxyphenyl) ether, 2,2-bis (4'-hydroxyphenyl) norbornane, 2,2'-bis (4'-hydroxyphenyl) adamantane, 6,6'-dihydroxy-3 , 3,3 ', 3'-tetramethyl-1,1'-spiroindan, hydro Paddy, resorcinol, hydrogenated bisphenol A, hydrogenated hydroquinone, hydrogenated resorcinol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, m-dihydroxyxylene, p-dihydroxy Xylene, 3,9-bis (2-hydroxy-1,1-dimethylethyl) -2,4,8,10-tetra-oxaspiro [8.8] undecane, 2,4'-dihydroxydiphenyl sulfone , 2,2-bis (4-dihydroxy-3-methoxyphenyl) propane, bis (hydroxymethyl) tricyclo [5.2.1.0 ^2.6 ] decane, 1,4-cyclohexanedimethanol, 1,4- Bis (2-hydroxyethoxy) -2-butyne, 4,4 '-(9-fluorenylidene) -bis- (2-phenoxyethanol), trans-2,3-bis (4-hydroxy Phenyl) -2-butene, 2,2-bis (3-cyclohexyl-4-hydroxyphenyl) propane, 1,1-dichloro-2,2-bis (4-hydroxyphenyl) ethylene, 1,1- Dibromo-2,2-bis (4-hydroxyphenyl) ethylene, bis (4-hydroxyphenyl) sulfoxide, 2,7-dihydroxypyrene, 9,9-bis (4-hydroxyphenyl) Fluorene, 2,7-dihydroxycarbazole, 2,6-dihi Doxytrianthrene, phenolphthalein, indane bisphenol and mixtures thereof. Bisphenols containing five- or six-membered aliphatic rings and described in US Pat. No. 4 982 014 may also be used as comonomer. Preference is given to using bisphenol A and TMC bisphenol (or mixtures thereof), with bisphenol A being most preferred. α, ω-dihydroxypolyolefin (e.g., Kraton Shell Liquid 2203, Kuraray TH-21®, etc.), α, ω-dihydroxypolycarbonate , α, ω-dihydroxypolyester and the like. Aromatic and aliphatic (or cycloaliphatic) alcohols containing two or more hydroxy groups per molecule can be used as branching agents (and sometimes crosslinkers). In addition to such polyfunctional alcohols such as 1,4-bis (4 ', 4'-dihydroxytriphenylmethyl) benzene, preparations containing nitrogen, for example 3,3-bis (4-hydroxyphenol)- It is also possible to use 2-oxo-2,3-dihydroindole or isatin biscresol. As a rule, they can also be used to branch compounds comprising at least two alkyl- or aryloxycarbonyl groups (crosslinking can occur at concentrations of at least 1 mol%).

The translucent polycarbonate blends produced according to the invention can be prepared by white pigments (titanium dioxide, preferably Kronos 2230) or other pigments (iron oxide, hexacyanoferrate (II) iron (III), chromium oxide, etc. ) And / or UV stabilizers and / or antioxidants, for example sulfur containing molecules (eg thioether based compounds such as dilauryl thiodipropionate, distearyl thiodipropionate, di Myristyl 3,3'- thiodipropionate, pentaerythritol tetrakis (β-laurylthiopropionate)), phosphite (phenyldiisodecyl phosphite, phenylisodecyl phosphite, triphenyl phosphite , Tris (nonylphenyl) phosphite, tricyclohexyl phosphite, tricresyl phosphite, tris (2,4-di-tert-butylphenyl) phosphite, tris (nonylphenyl) phosphite, bis (2,4 -Di-t-butylphenyl) pentaerytri Diphosphite, bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol diphosphite, 2,2-methylenebis (4,6-di-t-butylphenyl) octyl phosphite, 4,4 '-Diisopropylidenediphenolalkyl (C ₁₂ -C ₁₅ ), 4,4'-butylidenebis (3-methyl-6-t-butylphenylditridecyl phosphite), etc.), hindered phenol ( 1,1,3-tris (2-methyl-4-hydroxy-5-t-butylphenyl) butane, 4,4'-butylidenebis (3-methyl-t-butylphenol), n-octadecyl 3- (3 ', 5'-di-t-butyl-4'-hydroxyphenyl) propionate, pentaerythritol tetrakis (3- (3,5-di-t-butyl-4-hydrate Oxyphenyl) propionate, triethylene glycol bis (3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate, 1,6-hexanediolbis (3- (3,5- Di-t-butyl-4-hydroxyphenyl) propionate, 2,2'-methylenebis (4-methyl-6-t-butylphenol), 2,2'-methylenebis (4-ethyl-6- t-butylphenol), 2,2'-methylenebis (4-ethyl-6-t-butylphenol), 2-t-butyl-6- (3-t-butyl-2- Doxy-5-methylbenzyl) -4-methylphenyl acrylate, 2- (1- (2-hydroxy-3,5-di-t-butylphenyl) ethyl) -4,6-dinopentylphenyl acrylate , 4,4-thiobis (3-methyl-6-t-butylphenol), 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxy Benzyl) benzene, 2,2-thiodiethylenebis (3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, 3,9-bis (2- (3- (3- t-butyl-4-hydroxy-5-methylphenyl) propionyloxy) -1,1-dimethyl) -2,4,8,10-tetraoxaspiro [5.5] undecane, etc.), hydrophosphite, phospho Nitrate and / or diphosphonite, such as tetrakis (2,4-di-tert-butylphenyl) biphenylene diphosphonite, and the like.

The invention is illustrated by the following examples. The invention is not limited to the examples.

Example 1 Preparation of Polystyrene Solution in Cyclohexane

117.82 kg of distilled cyclohexane was transferred to a 500 L stirring tank under nitrogen atmosphere and heated to 50 ° C. 48.29 kg of polystyrene (PS) was then stirred in this solution for 4 hours. The solution was left for 24 hours at 70 ° C. while stirring. After cooling, 53.32 kg MTBE (methyl tert-butyl ether) was added to a stirred mixture at 50 ° C. under a nitrogen atmosphere. The stirred solution was then cooled to room temperature.

Example 2 Hydrogenation of Polystyrene with Ni Catalyst

A 40 liter autoclave equipped with a stirrer was charged with 21.943 kg polystyrene solution (21.943 kg solution = 4.829 kg PS + 11.782 kg cyclohexane + 5.332 kg MTBE) and then 625 g of Ni catalyst in 2.95 L MTBE was added. The autoclave was stirred, the corresponding hydrogen pressure was adjusted to 100 bar and the reactor heated to 160 ° C. while stirring. The pressure was automatically maintained at 100 bar during the reaction. When no more hydrogen was consumed the reaction was terminated and the reaction mixture was stirred for 2-4 hours. After removal of the catalyst by filtration, the solvent was evaporated to isolate the hydrogenated polymer.

Example 3 Blend of HPS with Polycarbonate in Kneader

The Haake Rheomix 600 double screw kneader, filled with 95 g of polycarbonate and 5 g of polyvinylcyclohexane, connected to a Haake Rheocord 90 processing unit, was heated to 290 ° C. (where Katron-Soder (Katron-Soder) T-20 measuring device was used under a nitrogen stream), kneading was carried out for 1 hour (40 rpm).

Example 4 Blend of HPS with Polycarbonate in Extruder

A Hake Leomix TW 100 twin screw extruder filled with 95 g of polycarbonate (Makrolon 1243) and 5 g of polyvinylcyclohexane connected to a Hake Leocord 90 processing unit was heated to 300 ° C. (where the Catron- Using the Soder T-20 measuring device). The fusion blend passed through the die of circular cross section was conveyed to a pelletizer (CF-Scheer & Cie) by a conveyor belt and a cooling trough (both Brabender OHG).

Example 5

Haze and transmittance tests were performed using a 60 mm × 60 mm × 2 mm sheet. Haze test was performed in accordance with ASTM-1003 / 290 using a HazeGard (BYK-Gardner) haze meter. Transmission spectra were recorded using a Perkin-Elmer Lambda 900 photometer equipped with a spherical detector (where air was used as reference). Table I below summarizes the haze and total transmittance tests.

Haze and total transmittance of polycarbonate comprising polymeric light diffusing agent number Sample thickness (mm) Light Diffusers Used Concentration (% by weight) Haze (%) Total transmittance at 450 nm (%) Total transmittance at 700 nm (%) One 0.5 HPS One 17 82 87 2 0.5 HPS 3 87 63 77 3 0.5 HPS 5 > 99 52 68 4 2 HPS One 32 69 82 5 2 HPS 3 > 99 32 54 6 2 HPS 5 > 99 23 40 7 2 PS One 26 48 72 8 2 Apel (registered trademark) One 45 44 65 9 2 Apel (registered trademark) 5 97 14 39 10 2 Arton (registered trademark) One 24 56 75 11 2 Arton (registered trademark) 5 91 22 50

Example 6

Stress / strain tests were performed with three dumbbell bars (170 mm × 10 mm × 4 mm) at room temperature using an Instron 5566 tester at a rate of 5 mm / min. Impact tests were performed with 80 mm × 10 mm × 4 mm bars. A specimen with a 2 mm V notch was used for the notch impact strength test. The mechanical properties of PCs including HPS 1% and 5% are summarized in Table II below.

Mechanical Properties of Polycarbonates Blended with HPS (Macrolon 1243) characteristic unit Sample A Sample B Furtherance weight% PC 99% + HPS 1% PC 95% + HPS 5% Glass transition temperature T _g ℃ 141 141 Bending impact test in the presence of notches Impact strength at room temperature a _k kJ / ㎡ 7.6 3.5 Maximum strength at room temperature N 286 268 Breaking characteristics Brittle Brittle Bending impact test without notch Impact strength at room temperature a _n kJ / ㎡ 213 213 Maximum strength at room temperature N 939 935 Breaking mode ductility ductility Deformation characteristics Modulus of elasticity MPa 1990 ± 100 1960 ± 100 Yield stress MPa 61.0 ± 0.1 61.6 ± 0.3 Yield strain % 5.8 ± 0.1 6.2 ± 0.3 The tensile strength MPa 62.9 ± 1.4 61.9 ± 0.8 Elongation at break % 90.8 ± 1.2 95.1 ± 2.2

Example 7

Extrusion of Double Wall Sheet

Pellets of HPS / polycarbonate blends comprising 3% by weight of HPS were prepared according to Example 5, followed by a 60 μm thick UV protective layer (Bayer AG-DP1-1244 / in a professional S-70 extruder (Bay AG) 5-55 / 0.54) with a double wall sheet (each layer having a thickness of 1 mm). The rotational speed is 38 rpm, the temperature at the feed is 270 ° C., the temperature of the first zone is 280 ° C., the temperature of the second zone is 270 ° C., the temperature of the third zone is 260 ° C., and the zones 4 to 6 and outlet The temperature was 250 ° C.

Example 8

The hail test according to DIN 53 443 evaluated the mechanical properties of the double wall sheet prepared according to Example 7. A twin-wall sheet (formed according to Example 6) 50 mm wide and 350 mm long was hit with a spherical pin of diameter 5 mm falling from a height of 20 mm. The pin was added at a weight of 36 kg. The test was performed at 23 ° C. Table III below shows the test results.

Fracture strength Fs, fracture elongation Ls and fracture energy Ws measured in the hail test of a double wall polycarbonate sheet (one layer = 1 mm) comprising 3 wt% HPS. exam Breaking characteristics Fs (kN) Ls (mm) Ws (J) One B 0.42 14.0 2.46 2 B 0.36 14.7 3.02 3 B 0.37 11.3 2.30 4 A 0.37 13.0 1.58 5 A 0.45 13.3 2.50 6 B 0.30 12.2 2.12 7 B 0.55 14.1 3.64 8 B 0.64 10.7 3.61 9 B 0.52 10.7 2.53 10 B 0.68 14.0 3.35 Average 0.47 12.8 2.71 * A: brittle / ductile; B: Smooth break

Example 9

Direct Extrusion of Double Wall Sheets from Polycarbonate and HPS

With a 60 μm thick UV protective layer (Bayarge-DP1-1244 / 5-55 / 054) in a professional S-70 extruder (Bayarge) without premixing polycarbonate and HPS (weight ratio 97: 3) Coextruded into a double wall sheet (each layer had a thickness of 1 mm). The rotational speed is 38 rpm, the temperature at the feed is 270 ° C., the temperature of the first zone is 280 ° C., the temperature of the second zone is 270 ° C., the temperature of the third zone is 260 ° C., and the zones 4 to 6 and outlet The temperature was 250 ° C.

Claims (10)

A polymer composition comprising a polycarbonate blended with a cycloolefin (co) polymer. The polymer composition of claim 1 comprising up to 25% by weight of cycloolefin (co) polymer. The polymer composition of claim 1 or 2 comprising hydrogenated polystyrene or hydrogenated polystyrene copolymer. The polymer composition according to any one of claims 1 to 3, wherein the polymer composition comprises a polycarbonate having a melt volume flow rate at 300 ° C of 3 to 8 cm 3/10 minutes. Polycarbonate blends comprising cycloolefin (co) polymers. Polycarbonate product or material comprising polycarbonate blended with cycloolefin (co) polymer. Use of cycloolefin (co) polymer as light diffusing agent in polycarbonate. Use of the polymer composition according to claim 1 for producing a light diffusion product or material. Use of the polycarbonate blend according to claim 2 for producing a light diffusion product or material. A process for producing a light diffusing polymer composition wherein a polycarbonate is blended with a cycloolefin (co) polymer.