PROCESS FOR PRODUCTION OF FIBER REINFORCED TAPE

Abstract

The invention relates to a process for the production of a tape comprising a plurality of sheathed continuous multifilament strands, wherein each of the sheathed continuous multifilament strands comprises a core that extends in the longitudinal direction and a polymer sheath which intimately surrounds said core, wherein each of the cores comprises an impregnated continuous multifilament strand comprising at least one continuous glass multifilament strand, wherein the at least one continuous glass multifilament strand is impregnated with an impregnating agent, wherein the process comprises the steps of: d) providing the plurality of sheathed continuous multifilament strands, e) placing the plurality of sheathed continuous multifilament strands in parallel alignment in the longitudinal direction, f) grouping the plurality of sheathed continuous multifilament strands, wherein steps e) and f) are performed such that the sheathed continuous multifilament strand can be consolidated and g) subsequently consolidating the plurality of sheathed continuous multifilament strands to form the tape, wherein the sheathed continuous multifilament strands are prepared by the sequential steps of a) unwinding from a package the continuous glass multifilament strands, b) applying the impregnating agent to the continuous glass multifilament strands to form the impregnated continuous multifilament strands and c) applying the sheath of the thermoplastic polymer composition around the impregnated continuous multifilament strands to form the sheathed continuous multifilament strands, wherein the sheathed continuous multifilament strands of step d) are the sheathed continuous multifilament strands obtained by step c) and wherein the sheathed continuous multifilament strands of step d) are subjected to step e) without cutting.

Claims

1. A process for the production of a tape comprising a plurality of sheathed continuous multifilament strands, wherein each of the sheathed continuous multifilament strands comprises a core that extends in the longitudinal direction and a polymer sheath which intimately surrounds said core, wherein each of the cores comprises an impregnated continuous multifilament strand comprising at least one continuous glass multifilament strand, wherein the at least one continuous glass multifilament strand is impregnated with an impregnating agent, wherein the process comprises the steps of: d) providing the plurality of sheathed continuous multifilament strands, e) placing the plurality of sheathed continuous multifilament strands in parallel alignment in the longitudinal direction, f) grouping the plurality of sheathed continuous multifilament strands, wherein steps e) and f) are performed such that the sheathed continuous multifilament strand can be consolidated and g) subsequently consolidating the plurality of sheathed continuous multifilament strands to form the tape, wherein the sheathed continuous multifilament strands are prepared by the sequential steps of a) unwinding from a package the continuous glass multifilament strands, b) applying the impregnating agent to the continuous glass multifilament strands to form the impregnated continuous multifilament strands and c) applying the sheath of the thermoplastic polymer composition around the impregnated continuous multifilament strands to form the sheathed continuous multifilament strands, wherein the sheathed continuous multifilament strands of step d) are the sheathed continuous multifilament strands obtained by step c) and wherein the sheathed continuous multifilament strands of step d) are subjected to step e) without cutting.

2. The process according to claim 1, wherein the continuous glass multifilament strands unwound in step a), the impregnated continuous multifilament strands formed in step b), the sheathed continuous multifilament strands formed in step c) are not cut during steps a)-g).

3. The process according to claim 1, wherein the process further comprises step h) of cutting the tape obtained by step g) into desired length.

4. The process according to claim 1, wherein steps e) and f) are performed by pulling the plurality of sheathed continuous multifilament strands through a slit die.

5. The process according to claim 1, wherein the consolidation of the plurality of sheathed continuous multifilament strands is performed in a consolidation unit, for example using a belt press.

6. The process according to claim 1, wherein step g) is performed by sequential steps of g1) heating and applying pressure on the plurality of sheathed continuous multifilament strand to obtain a product made of consolidated strands and g2) cooling and solidifying the product obtained by step g1), e.g. by chill rolls, a water bath, a blower a fan or a high speed air knife.

7. The process according to claim 6, wherein step g1) is performed by sequential steps of g1a) melting the plurality of sheathed continuous multifilament strand to merge the strands, e.g. by hot rolls, flat belts, an oven or a belt press and g1b) applying pressure on the product obtained by step g1a) to adjust its thickness, e.g. by calendaring rolls.

8. The process according to claim 1, wherein the amount of impregnating agent is 0.50 to 18 wt %, for example from 0.5 to 10.0 wt % or for example from 10.0 to 18.0 wt %, more preferably 1.5 to 8 wt %, even more preferably in the range from 2.5 wt % to 6.0 wt % based on the sheathed continuous multifilament strand, and/or wherein the impregnating agent has a melting point of at least 20° C. below the melting point of the thermoplastic polymer composition and has a viscosity of from 2.5 to 200 cSt at 160° C., and/or wherein the continuous glass multifilament strand comprises at most 2 wt % of a sizing composition based on the continuous glass multifilament strand, and/or wherein the sheath consists of a thermoplastic polymer composition, wherein the thermoplastic polymer composition comprises at least 60 wt %, for example at least 80 wt % of a thermoplastic polymer, and/or wherein the amount of the impregnated continuous multifilament strand is in the range of 10 to 70 wt %, for example 25 to 70 wt %, based on the sheathed continuous multifilament strand and wherein the amount of the sheath is in the range of 30 to 90 wt %, for example 30 to 75 wt %, based on the sheathed continuous multifilament strand and wherein the sum of the amount of impregnated continuous multifilament strand and the sheath is 100 wt %.

9. The process according to claim 1, wherein the thermoplastic polymer is a polyolefin, preferably wherein the polyolefin is chosen from the group of polypropylenes or elastomers of ethylene and α-olefin comonomer having 4 to 8 carbon atoms, and any mixtures thereof.

10. The process according to claim 1, wherein the melt flow rate of the thermoplastic polymer composition is in the range from 20 to 150 dg/min, preferably in the range from 25 to 120 dg/min, for example in the range from 35 to 100 dg/min as measured according to ISO1133 (2.16 kg/230° C.).

11. The process according to claim 1, wherein the thermoplastic polymer composition comprises at least 80 wt % of the thermoplastic polymer, for example at least 90 wt % polyolefin, at least 93 wt %, for example at least 95 wt %, for example at least 97 wt % of thermoplastic polymer, for example at least 98 wt % or for example at least 99 wt % of a thermoplastic polymer based on the thermoplastic polymer composition.

12. A tape obtained by or obtainable by the process according to claim 1.

13. (canceled)

14. An article comprising the tape of claim 12.

15. (canceled)

16. The article of claim 14 comprising a plurality of the tapes in the form of a laminate, a woven fabric, or both.

17. The article of claim 14 which is a component in an automotive application.

Description

[0083] In one embodiment, preferably the thermoplastic polymer composition comprises at least 80 wt % of a thermoplastic polymer, for example at least 90 wt % polyolefin, at least 93 wt %, for example at least 95 wt %, for example at least 97 wt % of thermoplastic polymer, for example at least 98 wt % or for example at least 99 wt % of a thermoplastic polymer based on the thermoplastic polymer composition. In a special embodiment, the thermoplastic polymer composition consists of a thermoplastic polymer.

[0084] In another embodiment, the thermoplastic polymer composition comprises at least 60 wt %, for example at least 70 wt %, for example at least 75 wt % and/or at most 99 wt %, for example at most 95 wt %, for example at most 90 wt % thermoplastic polymer.

[0085] The polypropylene may for example be a propylene homopolymer or a random propylene-α-olefin copolymer or a heterophasic propylene copolymer.

[0086] A propylene homopolymer can be obtained by polymerizing propylene under suitable polymerization conditions. A propylene copolymer can be obtained by copolymerizing propylene and one or more other α-olefins, preferably ethylene, under suitable polymerization conditions. The preparation of propylene homopolymers and copolymers is, for example, described in Moore, E. P. (1996) Polypropylene Handbook.

[0087] Polymerization, Characterization, Properties, Processing, Applications, Hanser Publishers: New York.

[0088] The α-olefin in the random propylene α-olefin copolymer is for example an α-olefin chosen from the group of α-olefin having 2 or 4 to 10 C-atoms, preferably ethylene, 1-butene, 1-hexene or any mixtures thereof. The amount of α-olefin is preferably at most 10 wt % based on the propylene α-olefin copolymer, for example in the range from 2-7 wt % based on the propylene α-olefin copolymer.

[0089] Polypropylenes can be made by any known polymerization technique as well as with any known polymerization catalyst system. Regarding the techniques, reference can be given to slurry, solution or gas phase polymerizations; regarding the catalyst system reference can be given to Ziegler-Natta, metallocene or single-site catalyst systems. All are, in themselves, known in the art.

[0090] Heterophasic propylene copolymers are generally prepared in one or more reactors, by polymerization of propylene in the presence of a catalyst and subsequent polymerization of a propylene-α-olefin mixture. The resulting polymeric materials are heterophasic, but the specific morphology usually depends on the preparation method and monomer ratio.

[0091] The heterophasic propylene copolymer as defined herein consists of a propylene-based matrix and a dispersed ethylene-α-olefin copolymer.

[0092] The propylene-based matrix typically forms the continuous phase in the heterophasic propylene copolymer.

[0093] The propylene-based matrix consists of a propylene homopolymer and/or a propylene-α-olefin copolymer consisting of at least 70% by mass of propylene and up to 30% by mass of α-olefin, for example ethylene, for example consisting of at least 80% by mass of propylene and up to 20% by mass of α-olefin, for example consisting of at least 90% by mass of propylene and up to 10% by mass of α-olefin, based on the total mass of the propylene-based matrix.

[0094] Preferably, the α-olefin in the propylene-α-olefin copolymer is selected from the group of α-olefins having 2 or 4-10 carbon atoms and is preferably ethylene.

[0095] Preferably, the propylene-based matrix consists of a propylene homopolymer.

[0096] The melt flow index (MFI) of the propylene-based matrix (before it is mixed into the composition of the invention) may be in the range of for example 0.3 to 200 dg/min as measured according to ISO1133 (2.16 kg/230° C.).

[0097] The propylene-based matrix is for example present in an amount of 50 to 85 wt % based on the total heterophasic propylene copolymer.

[0098] Besides the propylene-based matrix, the heterophasic propylene copolymer also consists of a dispersed ethylene-α-olefin copolymer. The dispersed ethylene-α-olefin copolymer is also referred to herein as the ‘dispersed phase’. The dispersed phase is embedded in the heterophasic propylene copolymer in a discontinuous form.

[0099] The MFI of the dispersed ethylene α-olefin copolymer may vary between wide range and may for example be in the range from for example be in the range from 0.001 to 10 dg/min (measured according to ISO1133 (2.16 kg/230° C. as calculated using the following formula:

[00001]$\mathrm{MFR}\mathrm{EPR}=10^{^}\left(\frac{\mathrm{Log}\mathrm{MFR}\mathrm{heterophasic}-\mathrm{matrix}\mathrm{content}*\mathrm{Log}\mathrm{MFR}\mathrm{PP}}{\mathrm{rubber}\mathrm{content}}\right)$

[0100] wherein MFR heterophasic is the melt flow rate of the heterophasic propylene copolymer measured according to ISO1133 (2.16 kg/230° C.),

[0101] MFR PP is the MFR of the propylene-based matrix of the heterophasic propylene copolymer measured according to ISO1133 (2.16 kg/230° C.)

[0102] matrix content is the amount of propylene-based matrix in the heterophasic propylene copolymer in wt % and

[0103] rubber content is the amount of ethylene α-olefin copolymer in the heterophasic propylene copolymer in wt %.

[0104] The dispersed ethylene-α-olefin copolymer is for example present in an amount of 50 to 15 wt % based on the total heterophasic propylene copolymer.

[0105] For example, the amount of ethylene in the ethylene-α-olefin copolymer (RCC2) is in the range of 20-65 wt % based on the ethylene-α-olefin copolymer.

[0106] The amounts of the propylene-based matrix and the dispersed ethylene-α-olefin copolymer, as well as the amount of ethylene in the ethylene α-olefin copolymer may be determined by .sup.13C-NMR, as is well known in the art.

[0107] In the heterophasic polypropylene, the sum of the total weight of the propylene-based matrix and the total weight of the dispersed ethylene-α-olefin copolymer is 100 wt %

[0108] The α-olefin in the ethylene-α-olefin copolymer is preferably chosen from the group of α-olefins having 3 to 8 carbon atoms and any mixtures thereof, preferably the α-olefin in the ethylene-α-olefin copolymer is chosen from the group of α-olefins having 3 to 4 carbon atoms and any mixture thereof, more preferably the α-olefin is propylene, in which case the ethylene-α-olefin copolymer is ethylene-propylene copolymer. Examples of suitable α-olefins having 3 to 8 carbon atoms, which may be employed as ethylene comonomers to form the ethylene α-olefin copolymer include but are not limited to propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexen, 1-heptene and 1-octene.

[0109] The elastomer of ethylene and α-olefin comonomer having 4 to 8 carbon atoms may for example have a density in the range from 0.850 to 0.915 g/cm.sup.3. Such elastomers are sometimes also referred to as plastomers.

[0110] The α-olefin comonomer in the elastomer is preferably an acyclic monoolefin such as 1-butene, 1-pentene, 1-hexene, 1-octene, or 4-methylpentene.

[0111] Accordingly, the elastomer is preferably selected from the group consisting of ethylene-1-butene copolymer, ethylene-1-hexene copolymer, ethylene-1-octene copolymer and mixtures thereof, more preferably wherein the elastomer is selected from ethylene-1-octene copolymer. Most preferably, the elastomer is an ethylene-1-octene copolymer.

[0112] Preferably, the density of the elastomer is at least 0.865 g/cm.sup.3 and/or at most 0.910 g/cm.sup.3. For example, the density of the elastomer is at least 0.850, for example at least 0.865, for example at least 0.88, for example at least 0.90 and/or for example at most 0.915, for example at most 0.910, for example at most 0.907, for example at most 0.906 g/cm.sup.3. More preferable the density of the elastomer is in the range from 0.88 up to an including 0.907 g/cm.sup.3, most preferably, the density of the elastomer is in the range from 0.90 up to and including 0.906 g/cm.sup.3.

[0113] Elastomers which are suitable for use in the current invention are commercially available for example under the trademark EXACT™ available from Exxon Chemical Company of Houston, Tex. or under the trademark ENGAGE™ polymers, a line of metallocene catalyzed plastomers available from Dow Chemical Company of Midland, Mich. or under the trademark TAFMER™ available from MITSUI Chemicals Group of Minato Tokyo or under the trademark Nexlene™ from SK Chemicals.

[0114] The elastomers may be prepared using methods known in the art, for example by using a single site catalyst, i.e., a catalyst the transition metal components of which is an organometallic compound and at least one ligand of which has a cyclopentadienyl anion structure through which such ligand bondingly coordinates to the transition metal cation. This type of catalyst is also known as “metallocene” catalyst. Metallocene catalysts are for example described in U.S. Pat. Nos. 5,017,714 and 5,324,820. The elastomer s may also be prepared using traditional types of heterogeneous multi-sited Ziegler-Natta catalysts.

[0115] Preferably, the elastomer has a melt flow index of 0.1 to 40 dg/min (ISO1133, 2.16 kg, 190° C.), for example at least 1 dg/min and/or at most 35 dg/min. More preferably, the elastomer has a melt flow index of at least 1.5 dg/min, for example of at least 2 dg/min, for example of at least 2.5 dg/min, for example of at least 3 dg/min, more preferably at least 5 dg/min and/or preferably at most 30 dg/min, more preferably at most 20 dg/min, more preferably at most 10 dg/min measured in accordance with ISO 1133 using a 2.16 kg weight and at a temperature of 190° C.

[0116] Preferably, the amount of ethylene incorporated into the elastomer is at least 50 mol %. More preferably, the amount of ethylene incorporated into the elastomer is at least 57 mol %, for example at least 60 mol %, at least 65 mol % or at least 70 mol %. Even more preferably, the amount of ethylene incorporated into the elastomer is at least 75 mol %. The amount of ethylene incorporated into the elastomer may typically be at most 97.5 mol %, for example at most 95 mol % or at most 90 mol %.

[0117] The thermoplastic polymer composition may contain the usual additives, for instance nucleating agents and clarifiers, stabilizers, release agents, fillers, peroxides, plasticizers, anti-oxidants, lubricants, antistatics, cross linking agents, scratch resistance agents, high performance fillers, pigments and/or colorants, impact modifiers, flame retardants, blowing agents, acid scavengers, recycling additives, coupling agents, anti-microbials, anti-fogging additives, slip additives, anti-blocking additives, polymer processing aids and the like. Such additives are well known in the art. The skilled person will know how to choose the type and amount of additives such that they do not detrimentally influence the aimed properties. In a special embodiment, the thermoplastic polymer composition consists of the thermoplastic polymer and additives.

[0118] Preferably, the amount of impregnated continuous multifilament strand is in the range of 10 to 70 wt %, for example in the range from 15 to 70 wt %, for example in the range from 20 to 70 wt % or for example in the range from 25 to 70 wt % based on the sheathed continuous multifilament strands. Preferably, the sum of the amount of impregnated continuous multifilament strand and the polymer sheath is 100 wt %.

[0119] Although the invention has been described in detail for purposes of illustration, it is understood that such detail is solely for that purpose and variations can be made therein by those skilled in the art without departing from the spirit and scope of the invention as defined in the claims.

[0120] It is further noted that the invention relates to all possible combinations of features described herein, preferred in particular are those combinations of features that are present in the claims. It will therefore be appreciated that all combinations of features relating to the composition according to the invention; all combinations of features relating to the process according to the invention and all combinations of features relating to the composition according to the invention and features relating to the process according to the invention are described herein.

[0121] It is further noted that the term ‘comprising’ does not exclude the presence of other elements. However, it is also to be understood that a description on a product/composition comprising certain components also discloses a product/composition consisting of these components. The product/composition consisting of these components may be advantageous in that it offers a simpler, more economical process for the preparation of the product/composition. Similarly, it is also to be understood that a description on a process comprising certain steps also discloses a process consisting of these steps. The process consisting of these steps may be advantageous in that it offers a simpler, more economical process.