HU197338B - Process for producing improved material for shoesole workable withinjection moulding - Google Patents

Abstract

Shoesole material having improved resistance to ageing, oil and chemicals is prepared by dynamic vulcanisation of a blend of styrene/butadiene or alpha -methyl styrene butadiene rubber and an at least partially crystalline olefin polymer at a temperature above the softening point of the olefin polymer. The compositions may also comprise other diene rubbers and styrene polymers.

Description

FIELD OF THE INVENTION The present invention relates to a process for producing injection molding footwear material with improved properties. Enhanced property includes improved oil and chemical resistance, flowability and aging resistance.

The vast majority of injection molding materials are now mainly based on styrene / diene - mainly styrene / butadiene - based block copolymers having a block polystyrene in the range of 25-35% by weight. In addition, ethylene / vinyl acetate (E / VAC) is also used very rarely and almost exclusively for the manufacture of microcellular foam soles (eg Belgian Patent No. 891,480).

Styrene / diene-based block copolymers are the oldest members of the family of thermoplastic elastomers and are produced by anionic or live polymerization. In addition to this thermoplastic elastomer, polymers, plasticizers, fillers, processing aids, anti-aging agents, pigments, other additives, and sometimes foaming agents, are included as ingredients in multi-component shoe soles.

Among the disadvantages of soles made from styrene / diene-based thermoplastic elastomers are the necessity of extremely unfavorable oil and chemical resistance, the difficult processability (injection molding) caused by the low flow rate, and the presence of unsaturated double bonds. Occasionally, the foregoing disadvantages are further exacerbated by the shrinkage of the form, since shrinkage of the soles is very sensitive to slight changes in the constituents and is essentially dependent on the chemical structure of the styrene / butadiene-based thermoplastic elastomer (segment length, linear or star shape). Another source of difficulty is that due to their sophisticated manufacturing technology, styrene / diene-based block copolymers can only be manufactured by some companies (ANIC, PINA, PHILLIPS PETROLEUM, SHELL), which in some cases may be used by the processor. can make the employee vulnerable.

There are many examples in the literature of increasing the oil and chemical resistance of styrene / diene block copolymers. No. 4,209,594. U.S. Pat. discloses polystyrene grafted with alkyl acrylate, U.S. Pat. A US patent also discloses similar uses of chlorinated polyethylene (CPE) in addition to conventional prescription ingredients. In addition to these polar additives, crystalline polyolefins such as High Density Polyethylene (NSPE) (U.S. Pat. No. 4,216,132, Linear Low Density Polyethylene (LKSPE)) No. 4,495,323. US patent) as an additive has also been found to be effective in improving oil resistance. However, it is also known in the literature to use a non-polar or highly crystalline thermoplastic but a polar thermoplastic elastomer such as a carboxylated styrene / butadiene block copolymer (U.S. Pat. No. 4,409,357). The common disadvantage of these systems is described under the heading of compatibility. Incompatible or improperly formed or rendered components during mixing lead to unfavorable folding resistance of the base material, possibly to scaly separation or fracture.

There are basically two ways to improve injection molding and processability. The use of metal soap slides is severely limited, since their migration to the surface significantly reduces the adhesion of the soles. Processors therefore prefer the use of polymer-type flow enhancers and thus use polystyrene and impact-resistant polystyrene (e.g., Japanese Patent Publication No. 80,118,944 / Czechoslovak Patent No. 189,445), which also serve to adjust the hardness of the final product. In addition, examples of the use of poly (α-methylstyrene) are particularly known (U.S. Patents 4,409,357 and 4,495,323). However, homogenization of polystyrene and styrene copolymers in the blend is very difficult, as special twin screw extruders are capable of doing so.

The addition of crystalline polyethylenes (U.S. Patents 4,216,132 and 4,495,323) may also increase the flow rate of the mixture, but their presence adversely affects the adhesion of the backing material. This latter difficulty can be found in the cited 189,445. Czechoslovakian patent E / VAC. In fact, polymers grafted with polar monomers (e.g., U.S. Pat. No. 4,209,594) are intended to provide or possibly improve adhesive bonding. CPE No. 4,225,500. As well as the use of carboxyl-terminated thermoplastic elastomers (U.S. Patent No. 4,409,357).

To eliminate the presence of aging-related double bonds, U.S. Patent No. 4,209,594. U.S. Pat. hydrogenated, i.e. post-saturated styrene / diene rubber. Another option for removing double bonds is to vulcanize the sole at the same time as the jam, which necessarily entails loss of thermoplasticity and recyclability. This is the case for vulcanizable soles of styrene / butadiene rubber (SBR) based on a random distribution of its constituents (Hungarian Patent No. 182,250).

In the literature IC SULO, S, KOPÁL, P. Kozarstvi 1986 (5), (114); reference is made to so-called polypropylene or branched polyethylene and SBR rubber or natural rubber. for the production of dynamic vulcanizates. However, they do not fully meet the requirements for sole use, so under normal circumstances they cannot be glued or painted; inadequate folding resistance; they are difficult to process due to their injection molding and low flowability, and their resistance to aging is extremely poor.

Summarizing the current state of the art, it is recognized that the use of styrene / diene based thermoplastic elastomers is not known for a shoe-based outsole that is simultaneously characterized by good oil and chemical resistance, good fluidity and aging resistance, and other requirements for solids. etc.).

It is an object of the present invention to provide an injection molding substrate which has improved chemical resistance, processability and aging resistance compared to conventional styrene / butadiene block copolymers and other dynamic vulcanisation materials.

It is a further object of the present invention to provide this support without the use of styrene diene-based block copolymers.

Finally, it was a further object of the present invention that this improved molding base can be manufactured on equipment used in the rubber industry.

The present invention is based on the surprising discovery that a sole that satisfies the above requirement can be obtained if a styrene / butadiene rubber (SBR) with a statistical monomer distribution, possibly in the presence of other diene rubbers, is a crystalline, grafted, polar oC-olefin copolymer and in certain proportions, it is plasticized at a temperature above the softening point of the polyolefin, i.e. under shear and pressure, possibly with other additives known per se, in the presence of a peroxide or sulfur vulcanization system.

The present invention is further based on the recognition that the flow properties of the shoe sole thus prepared can be adjusted by the appropriate choice of the melt index of the polyolefin used and the Mooney viscosity of the rubber used, and the quality and quantity of the vulcanization system.

It is very surprising to those skilled in the art that, despite the crosslinking agents used, a thermoplastic molding material can be obtained which, moreover, is easily processed due to its good flowability. Experience has shown that the formation of a bulk material would be expected. It is also surprising that an oil and chemical resistant product is known to be available using non-oil and chemical resistant diene rubbers.

Finally, it is also surprising that the product of the process has a very good aging resistance, since the presence of vulcanizers should trigger an increased aging of the polyolefin.

Accordingly, the present invention provides a process for producing injection-molded shoe soles with improved properties compared to styrene / butadiene block copolymers, thermoplastic polyolefin, diene rubber, optionally thermoplastic polystyrene, and other additives known in the art such as plasticizer, filler, filler, characterized in that the thermoplastic polyolefin comprises from 20 to 30 parts by weight of a polar α-olefin copolymer and a polar graft polyolefin, from 20 to 30 parts from an apolar polyolefin and from 40 to 60 parts by weight of a diene rubber and a thermoplastic polyolefin component. measured at 190 ° C under a load of 21.2 N and having a crystalline proportion of more than 5% by weight, the component used as diene rubber is styrene-butadiene and polybutadiene rubber and the styrene content of styrene-butadiene rubber is 10- 50 Mooney viscosity at 100 ° C measured with L rotor 4 min. afterwards, plasticization is carried out in the presence of known peroxide or sulfur crosslinking agents in the range of 25-65 M'Joney.

Preferred polar polyolefins according to the invention are maleolate (grafted with maleic acid or maleic anhydride), graft polyolefins, preferably ethylene / vinyl acetate copolymer, ethylene / ethyl acrylate (E / EA) copolymer, and apolar type. linear low and high density polyethylene, polypropylene homo copolymers, and combinations thereof may be used. In addition to the obligatory SBR types, polybutadiene (BR), polyisoprene (IR), natural rubber (NR), and a combination thereof, are preferred as diene rubbers.

Preferred peroxide systems according to the invention are dicumyl peroxide, 1,3-bis (t-butylperoxyisopropyl) benzene, 2,5-dimethylhexane-2,5-di-t-butylperoxide; 2,5-dimethylhexine-3-2,5-di-t-butyl peroxide, etc. of the sulfur types, surface-treated sulfur, colloidal sulfur, and sulfur donor compounds may be used in combination with known accelerator systems.

Suitably, the sole according to the invention is prepared by first adding the polyolefin to the rubber mixing apparatus, then adding the rubber and other additives (fillers, plasticizers, dyes, etc.) until the temperature of the mixture is above the softening point of the polyolefin. and / or internal friction through the formulation components, followed by the addition of the crosslinking system.

The hot material leaving the mixer is flattened and cut into strips for further use, possibly in granular form.

The main advantages of the process according to the invention are as follows:

hard-to-obtain, hard-to-access styrene / butadiene-based block copolymers or they may be replaced by a mixture of thermoplastic materials and rubbers manufactured in high mass;

- since the process can produce shoe soles that can be directly further processed, significant energy and material savings can be made as compared to processes using styrene / butadiene block copolymers and their addition. In this case, the base material is formed on investment and labor intensive mixing extruders, whose energy consumption exceeds that of the rubber industry mixers. Material saving results in a change in quality, color etc. switching from batch to batch operation rubber industry mixers may take place while continuous extruders require cleaning and cleaning;

the base material produced by the process has improved oil and liquid resistance to conventional styrene / diene based block copolymers;

- the flow properties of the bedding material of the process are very favorable and can be adjusted according to the particular requirements by the implementation of the procedure and by prescription variations;

- the aging tendency of the soles produced by the process is lower in natural and artificial conditions than in the styrene / butadiene block copolymer on which the comparison is based; respectively. other dynamic vulcanizates well known in the literature;

- adjustable and adjustable shrinkage of the soles according to the method;

the adhesive, abrasion resistance, tear resistance, durable folding, slip resistance of the fabric made according to the process is better than that of the styrene / butadiene block copolymers.

The invention is illustrated by the following non-limiting examples.

Example 1

In a 2-liter Werner-Pfleiderer type internal lab mixer, two mixtures of the following composition were prepared at 170 ° C at n = 30 / min with a rotation time of 10 minutes. The mixtures so prepared were granulated and sample plates were injected on a screw-piston injection molding machine for testing.

Blend creators the (crowd- quantity b crowd- section) section) Ethylene / vinyl acetate copolymer * 35 35 S styrene - b u tadié n rubber 60 60 Sulfur 2 - N, N * -difenil- guanidine *** 1 Tetrameil-tiuram- disulfide **** 0.2 Dicumyl peroxide - 1 Quinoline-type anti-aging ***** 1 1 Polyethylene ” ⁰⁰⁰ ® 5 5

x = Evathane 2805 - ICI Product vinyl acetate content 28.5; crystalline ratio 8%; melt index MFI (190 ° C 21.2 N) = 5 dg / min xx = SSS-30 ARKP / N-Soviet styrene content 30% Mooney viscosity (ML-1 + 4) at 100 ° C = 42 xxx = Denax - Bulgarian product xxxx = Tiuram M - Monsanto product xxxxx = Felctol H - Monsanto product xxxxxx = Tipolen FA 2210 - TVK product

The properties of the above composition are summarized in the attached table. It is clear that the sole of the example has an extremely low flow rate, which allows easy processing.

The oil and chemical resistance of the outsole is outstanding against isooctane, paraffin oil and instrument oil. This also allows the use of outsole material for work safety footwear.

Above average, the results of aging resistance tests are best seen in the slight change in tensile strength and elongation at break under aging conditions. (Similar conclusions can be drawn from comparing their bond strength before and after aging.)

Linear shrinkage values for the sole material are also advantageous, allowing the production of precision molded pads.

Surprisingly, the results of foot wear and folding sharpness, as well as the tear resistance values, are excellent. These indicators, together with the excellent results of the bonding tests that determine the workability, are decisive for the shoe user of the material. The data in the table also show that the change in the vulcanization system (system 1 / a-l / b) does not significantly affect the physical-mechanical parameters.

Example 2

In a Werner-Pfleiderer type 2L internal mixer, two mixtures of the following compositions were prepared at 160 ° C; n = 50 rpm using a rotor speed. The stirring time was 8 minutes. Sample plates were made from the granulated mixture by injection molding machines on a screw piston.

Mixtures of constituents a (parts by weight) (parts by weight)

Ethylene / vinyl acetate copolymers » 20 20 Polyethylene »» 20 20 S styrene-b u tadiene rubber »» » 60 60 Sulfur 2 - 2,2-dibenzoyl-tri- aryl disulfide »» * » 1.5 N, N'-diphenyl- guanidine »» * »» 1.5 3.3, 6.6 9.9 Hexamethyl-1,2 4,5-tetracyclononane 2 Kaolin 30 30 Oil Tool 8 8

x = Evathane 2005 - crystalline product ICI: 15%; MFI = 5 dg / min

XX = Tipolen FA 2210 - Hungarian crystalline ratio: 30%; MFI product = 0.32 xxx = As in Example 1 xxxx = As in Example 1 xxxxx = As in Example 1

The advantages shown in Example 1 are present despite the high polyethylene content. The high processability (low flowability) of the material is combined with good oil and chemical resistance compared to TR base materials made from SBS base polymer in a conventional manner (Example 6 blend). Changes in the vulcanization system (sulfur, peroxide) do not represent a significant change in the physical characteristics of the bulk material.

Example 3

In the Farell-Bridge rapid mixer, two mixtures were prepared according to the following composition. (Mixing parameters: mixing temperature: 170 ° C rotor speed: 45 / min, mixing time: 6 min.)

Following granulation of the mixture, plates were made on a screw-piston injection molding machine.

Blend creators the (Phr) b (Phr) Ethylene / ethyl akrllát copolymers » 15 15 Maleinate Polyethylene » ³ '10 10 Polypropylene »» » 25 25 S styrene - rubber »» »» 25 25 polybutadiene rubber »» »» » 25 25 Sulfur N, N'-diphenyl- guanidine »*» * »* 1.5 1.5 Tetramethyl thiuram disulfide »» »» »» Quinoline anti-aging »» »» »» Natural zeolite 600 Extraction oil - 200

x = crystalline fraction of Lucobit - BASF product (ethylene / ethyl acrylate copolymer / bitumen): 6%; MFI = 3 dg / min.

xx = 5% crystalline polyethylene grafted with maleic acid 22%; MFI = = 2.5 dg / min xxx = Tipolen K 823; MFI 0.1 dg / min.

TVK product xxxx = Solprene 303 - Phillips product

Styrene content 48%; ML (1 + 4) at 100 ° C = 45 xxxxx = Plasticator 32 - GDR product ML (1 + 4) at 100 ° C = 600 xxxxxx = 1 Example xxxxxxx = Example 1

From the data in the attached table, it can be seen that, despite its high filling ratio and softener content (3 / b blend), this sole also has the advantageous properties highlighted by the patent (outstanding oil and chemical resistance, good fluidity, low shrinkage).

Example 4

In a 120 liter Commerio-type internal mixer at 190 ° C; At a rotor speed of n = 60 rpm, the following composition was prepared with a stirring time of 4 minutes. After crushing the mixture, plates were injection molded on a screw piston injection molding machine.

-510

Blend creators quantity (Phr) polypropylene * 10 Ethyl n / vinyl acetate copolymer ** 30 Polieztirol *** 20 Styrene-butadiene rubber **** 20 Natural rubber **** 10 Polyisoprene ****** 10 Surface treated with sulfur 0.4 Tetramethylthiuram disulfide ******* 1 talcum 100 Instrument oil 20 Phenolic Antioxidant ******** 1 Pigment 1

χ = Tipolen K 823- TVK Product xx = Example 1 xxx = PSZM-115 - Soviet Product

MFI = 8 dg / min. xxxx = Example xxxxx = Smoked I. - Malayalam product

ML (1 + 4) 100 ° C = 48 xxxxxx = Cariflex IR-Shell

ML (1 + 4) 100 ° C = 52 xxxxxxx = Example 1 xxxxxxxx = Example 1

Based on the properties compiled in the table, it can be concluded that the mixture of Example 4 also fulfills our objectives.

Example 5 In a 1 liter Werner-Pfleiderer type laboratory mixer, a mixture of the following composition was prepared at 150 ° C at n = 80 rpm for 5 minutes. After granulating the mixture, sample plates were formed by injection molding.

Quantity of ingredients in the mixture (parts by weight)

Ethylene / vinyl acetate copolymer * 42

Atactic polypropylene ** 8

Styrene-butadiene rubber *** 50

Sulfur

Tetramethylthiuram disulfide **** 0.2

N, N'-diphenylguanidine ™ * 2

Quinoline-type anti-aging »* ® ⁰⁰ * 1

Dolomites 50

Instrument Oil 5

Zinc Stearate Slipper '1 x = 1. Example xx = Tipolen APP-A - TVK Product xxx = Example 1 xxxx = Example 1 xxxxx = Example 1 xxxxxx = Example 1

The physico-mechanical and chemical properties of the sole of Example 5, summarized in the attached table, demonstrate the product's excellent shoe use. It is associated with excellent oil resistance, flowability, aging resistance, low shrinkage, low wear, good fold resistance, high breaking strength and good adhesion.

Example 6 (reference mixture)

1-5. In order to illustrate the advantageous properties of the blends described in Example 1A, a blend of thermoplastic rubber of conventional composition and preformation is based on SBS block copolymer. Mixture components corresponding to the following composition were mixed at 130 ° C in a shaker mixer; then homogenized in a two-screw extruder and granulated. The sample plates required for the tests were injected on a screw-piston injection molding machine.

Blend creators quantity (Phr) Styrene butadiene styrene block copolymer * 60 Polystyrene** 20 Ethylene / vinyl acetate *** copolymer 20 Silica **** 10 Instrument oil 5 Quinoline type anti-aging ***** 1

x = Solprene 1205 - Phillips Petrolleum xx = 4. Example xxx = Example 1 xxxx = Suprasil - NDK Product xxxxx = Example 1

The properties of the material shown in the attached table illustrate that the conventionally prepared base material has a lower fluidity, oil and chemical resistance, and aging resistance than the base materials described in Examples 1-5. Shrinkage and wear, which is crucial for use as a footing material, is also weaker than similar products of the patented product.

-612

EXAMPLE 7 By way of comparison, dynamic vulcanization formulations were prepared reflecting the state of the art. SULO 5, 5

Kopál P, Kozarstvi 1986 (5), 114; (Table 1)

In the Forrel-Bridge quick mixer, the following 4 mixtures were prepared.

(Mixing temperature 160 ° C, rotor speed: 8 rpm; mixing time 6 minutes) 10

Following granulation of the mixture, test slides were prepared on a screw-piston injection molding machine to determine physical indicators.

Blend creators (the) (B) parts by weight (C) wit (D) (E) Natural rubber * 55 50 - - - SBR Rubber ” ¹ - - 60 55 55 Polypropylene "® 45 - 40 - - polyethylene ™™ - 30 - 45 45 Nail - 20 - - - Ultrasil VN-3 - - - 20 - ZnO 4 3 - 4 - TMTD 1 1.2 - 1 - stearine 1 0.5 - 1 - From F to H 0.5 0.5 0.6 0.5 0.6 MBTS - 0.6 - - - dicumyl -peroxide - - 0.6 - 0.6

x = Smoked I - Malaysia! product (MLI / 1 + 4/100 ° C = 48) xx = SKS-30 ARKP / N - Soviet product xxx = Tipplen K 823 - TVK product xxxx = Tippolen FA 2210 - TVK product

TMD = Tetramethylthiuram disulfide

MBTS = dibenzthiazyl disulfide

The physical indicators (columns 7 / a; 7 / b; 7 / c; 7 / d) in the attached table show that these compositions do not fulfill the requirements for sole use at two significant points,

- sustained folding caused specimens to be fractured or cracked;

- the samples cannot be glued by the usual methods.

However, there are several other indicators examined. they fall short of the physical indicators provided by the formulas 1-5, such as:

- in all cases, the change in the strength indexes (tensile strength, elongation at break) in the case of artificial aging is around 50%, indicating a strong tendency of the samples to age;

- the melt flow index, oil and chemical resistance, and slip resistance values are well below those of Examples 1-5.

On the basis of the above, it can be seen that the composition of our solution has significantly better properties than the compositions closest to our application.

This is evidenced by the advanced nature of our solution.

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Claims (3)

Patent Claim Point A process for the production of a molding footwear material having improved properties by injection molding using one or more members of a thermoplastic polyolefin, diene rubber, optionally thermoplastic polystyrene and other additives known per se, such as a plasticizer, filler, excipient, dye, curing agent, as a polyolefin, a mixture of 20 to 30 parts by weight of a polar α-olefin copolymer and a polar graft polyolefin, 20 to 30 parts by weight of apolar polyolefin and 40 to 60 parts by weight of diene rubber in which the thermoplastic polyolefin component has a melt index at 190 ° C measured between 0.1 and 30 dg / min and 5 crystalline fractions above 5% by weight and having a styrene content of 10-50% by weight of styrene butadiene and polybutadiene rubber as component of diene rubber, Mooney 10 viscosity measured at 100 ° C with L rotor 4 min. after about 25-65 Mooney in the presence of known peroxide or sulfur crosslinking agents in known manner.