MXPA98008754A - Film of poliolefina, compositions and resinasutiles for the same and method for its preparation - Google Patents

Abstract

The invention relates to a mixture of a first component selected from talcs and a second component selected from feldspars, nephelines and nepheline syenites, wherein the ratio of the first component to the second component provides an improved abrasivity property. The invention further relates to a blocking agent made from such a mixture, this mixture provides in a polyolefin film. This invention also relates to a polyolefin resin composition having the mixture therein, as well as to films made therein.

Description

POLYOLEFINE FILM. COMPOSITIONS AND USEFUL RESINS FOR THE SAME AND METHOD FOR PREPARATION FIELD OF THE INVENTION This invention relates to polyolefin resin compositions, precursor materials used therein, and films made thereof. Most particularly, the invention relates to the use of a combination of talc and feldspar, nepheline and / or nepheline syenite.

BACKGROUND OF THE INVENTION The invention pertains to polyolefin resin compositions which are designed to produce clear films having a satisfactory ability against block formation, and wherein the anti-blocking agent exhibits low abrasivity. These films can be used in a wide range of packaging and film coating applications. Polyolefin films are widely used for packaging worldwide and are increasingly replacing traditional materials such as paper. High clarity in polyolefin films allows easy observation and identification of package contents. However, when plastic films are produced, there is a tendency for two or more layers of contacting film to adhere or "form blocks", making it difficult to separate the film, open the bag or locate the film. end of the roll. Commercially, it is required to add inorganic mineral fillers to polyolefin films to reduce block formation. It is well recognized that films produced from resins containing anti-blocking fillers have a rougher surface, which reduces intimate contact between the layers of the film and reduces block formation, hence the term "antiblocking agent" It is applied to such fillers. Not all inorganic fillers are effective anti-block agents and some effective antiblocks have other problems (such as high cost, high abrasivity, adverse effect on optics, and health risk) which limits their commercial utility. The goal is to add as little antiblock agent as possible to reduce the block forming force to the required level, as long as adverse effects on the optical properties of the film and other aspects such as wear on the equipment are minimized. treatment. Diatomaceous earth has been widely used as a moderately effective antiblock agent, but has the following adverse attributes: soft film haze, poor film clarity, very high abrasiveness, and moderately expensive. Talc is also widely used in certain polyolefin formulations as a moderately effective antiblocking agent. Its advantages over diatomaceous earth are lower cost, excellent clarity in the film, and a very low abrasivity. However, commonly its film turbidity is only light and would not be suitable for high clarity packaging applications. Although nepheline syenite or feldspar have been considered as antiblocking agents for high clarity film applications (due to their optical refractive index which is closer to that of polyethylene), they are relatively ineffective in reducing block forming forces , and has a very high abrasivity. The abrasiveness of inorganic antiblocking agents is of importance for several reasons. Antibacterial high abrasion agents will contribute to the rapid wear of the mixing and treatment equipment. When wear reaches the point where the dimensions of the equipment change in critical areas, both the dispersion of the additives in the resin and the performance ratios can be adversely affected. In such cases, the quality of the product may deteriorate and production costs may increase, particularly if the equipment must be taken out of service and new parts purchased to replace the worn parts of equipment. Even more, abrasion of the equipment will introduce metal contamination into the plastic product, which may have a detrimental effect on the stability or color of the product, or both. Antiblock agents with low abrasivity are preferred for these reasons. There have been many attempts by others to solve the problem of balancing the properties of non-block formation and turbidity of the polyolefin film, but no one has taken into account what concerns the clarity of the film and the abrasiveness of the antiblocking agent and the cost (which are all necessary considerations for a viable commercial product). The existing situation is that an effective antiblocking formulation has not yet been found for high clarity polyolefin films with low abrasiveness of the antiblocking agent.

BRIEF DESCRIPTION OF THE INVENTION The present invention relates to a mixture of a first component selected from talcs and a second component selected from feldspars, nephelines and nepheline syenite, wherein the ratio of the first component to the second component provides a significantly lower abrasive property than that expected by law of mixtures. Additionally, the invention relates to an antiblock agent comprising a mixture of a first component selected from talcs and a second component selected from feldspars, nephelines and nepheline syenites, wherein the ratio of the first component to the second component provides an action against formation of blocks significantly greater than any of the components alone. This agent does not result in a significant loss of optical properties when used in a polyolefin film. This invention also relates to a mixture of a first component selected from talcs and a second component selected from feldspars, nephelines and nepheline syenites, wherein the ratio of the first component to the second component provides a significantly lower abrasivity property than that expected from the Mixture law and wherein the ratio of the first component to the second component provides a significantly greater anti-block action than any of the components alone. This invention also relates to a polyolefin resin composition, wherein the ratio of the first component to the second component further provides an anti-blockage action significantly greater than any single component, and the abrasive property of the first and second component in the mixture is around of 80% or less than the expected of the law of mixtures. Also, the invention relates to a polyolefin film comprising the polyolefin resin composition, and such a film can be made from the above components having a significantly lower abrasivity property than that expected from the blending law, and the film can have a significantly greater anti-blocking action than when any single component is made. An advantage of the present invention is that blends and polyolefin resin compositions can be used to produce films having satisfactory anti-block and optical properties (turbidity and clarity). The precursor mixture may also have a low abrasivity. The combination produces a synergistic effect where the degree of antiblock action is unexpectedly greater than when they are alone, while still retaining the optical properties and has a low abrasivity.

RELATED TECHNIQUE In Matsumoto et al., "Method for the Production of Antifog Poiyolefin Film" Japanese Kokai No. 60 (1985) - 49,047, there is a method described for using the composition of a polyolefin resin containing the polyolefin resin, two types of inorganic fillers. in very fine powder, and an unsaturated fatty acid amide and mixed polyol ester of fatty acid. In Hayashida et al., "Poiyolefin Resin Composition", of the patent of E.U.A. No. 5,346,944, there is disclosed a polyolefin resin composition having an antiblock agent and, optionally, an antistatic agent, an anti-fogging agent and antioxidants.

DESCRIPTION OF THE MODALITIES OF THE INVENTION One embodiment of the present invention is a mixture of a first component selected from talcs and a second component selected from feldspar, nepheline and nepheline syenites, wherein the ratio of the first component to the second component provides a significantly lower abrasive property than that expected from the law of mixtures. Preferably, the abrasive property is about 80% or less than that expected from the blending law, very preferably it is about 50% or less than that expected from the blending law. This mixture has use as a precursor material usable in polyolefin resin compositions and in films and other types of products, such as sheets, molds and molding compounds, made of such polyolefin resin compositions. The polyolefins considered suitable for the present invention may be any polyolefin, which may be transparent, crystalline, and capable of forming a self-supporting film. Non-limiting examples include crystalline homopolymers of an α-olefin with carbon numbers ranging from 2 to 12 or a mixture of 2 or more crystalline copolymers or ethylene-vinyl acetate copolymers with other resins. Also, the polyolefin resin can be a density polyethylene, a low density polyethylene, a linear low density polyethylene, polypropylene, propylene-ethylene copolymers, poly-1-butene, vinyl acetate-ethylene copolymers, etc.; and polyethylenes of low and medium density. Additional examples are represented by random or block copolymers of polyethylene, polypropylene poly-r-methylpentene-1, and ethylene-propylene, and ethylene-propylene-hexane copolymers. Among them, copolymers of ethylene and propylene and those containing 1 or 2 selected from 1-butene, 1-hexane, 4-methylpentene-1, and octene-1 (the so-called LLDPE), are particularly suitable. The polyolefin resin production method used in the present invention is not limited. For example, it can be manufactured by means of ionic polymerization or radical polymerization. Examples of polyolefin resins obtained by ionic polymerization include homopolymers such as polyethylene, polypropylene, poly-1-butene, and poly-4-methylpentene and ethylene copolymers obtained by the copolymerization of ethylene and α-olefin, α-olefins having from 3 to 18 carbon atoms such as propylene, 1-butene, 4-methylpentene-1, 1-hexene, 1-octene, 1-dequene, and 1-octadecene are used as α-olefins. These α-olefins can be used individually or as two or more types. Other examples include propylene copolymers such as the copolymers of propylene and 1-butene. Examples of polyolefin resins obtained by radical polymerization include ethylene alone or ethylene copolymers obtained by copolymerization of ethylene and radical polymerizable monomers. Examples of radically polymerizable monomers include unsaturated carboxylic acids such as acrylic acid, methylacrylic acid and maleic acid esters and acid anhydrides thereof, and vinyl esters such as vinyl acetate. Concrete examples of esters of unsaturated carboxylic acids include ethyl acrylate, methyl methacrylate and glycidyl methacrylate. These monomers polymerizable with radicals can be used individually or as two or more types. The talc in the present invention is selected from those talcs usable for the manufacture of polyolefin materials. A typical talc is monoclinic in the crystal structure, has a specific gravity of about 2.6 to 2.8 and an empirical formula of Mg3 YES 0 ^ 0 (0H) 2. Preferably, the average particle size of the talc used is from about 0.1 microns to about 10 microns. The second component is selected from feldspar, nepheline and nepheline syenites, or a mixture thereof. Such materials are known to those skilled in the art and are conveniently defined in "Minerals and Rocks", The Ne? Encvclopedic Britannica. Vol. 24, p. 151-157, 175-179, Encyclopedia Britannica, Inc. (Chicago, 1986), incorporated herein by reference in its entirety. Preferably, the average particle size of the second component used is about 0.1 microns and about 10 microns. The mixture is made by any convenient mixing operation which does not reduce or adversely agglomerate the component. Such mixing may be, but is not required to be, integrated into the milling operation, if any, of the components. The abrasive property can be determined using the Einlehner AT 1000 abrasion tester and the methodology recommended by the manufacturer, since the equipment and methods are known in the art. The manual "Einlehner Abrasion Tester AT 1000" is hereby incorporated by reference in its entirety. In another embodiment, the present invention is an antiblock agent comprising a mixture of a first component selected from talcs and a second component selected from feldspars, nephelines and nepheline syenites, wherein the ratio of the first component to the second component, provides an action against Block formation significantly greater than any single component. In a preferred embodiment, the proportion of the two components is from about 1/3 to about 3/1; that is, from about 25 percent to about 75 percent talc, the rest being the second component. Most preferably, the ratio is from about 44/55 to about 75/15. Preferably, the antiblock action produces a degree of block formation of about 85 percent or less than any single component; a degree of block formation of about 75 percent or less is preferable to any component alone; and even a block formation degree of about 55 percent or less than any single component is very preferable. The antiblock agent can be used to produce a polyolefin film and when so used, preferably the mixture of the first component and the second component does not cause a significant loss of optical properties such as clarity and turbidity. In another embodiment, the invention is a mixture of a first component selected from talcs and a second component selected from feldspars, nephelines and nepheline syenite, wherein the ratio of first component to second component provides a significantly lower abrasivity property than expected from the mixing law and wherein the ratio of the first component to the second component provides an action against block formation significantly greater than any single component. Preferably, the ratio of the first and second components varies from about 1/3 to 3/1, and the abrasive property of the first and second components in the mixture is about 50 percent or less than expected from the law of the mixing and the agent against block formation produces a degree of block formation of about 50 percent or less. The mixture of the first and second components can be produced as an aggregate precursor mixture in a polyolefin resin composition or formulated at the site, either in a polyolefin resin composition or as a portion of the production of the polyolefin film. The order of addition of the separated components is not critical. When formulated at the site, the components can be added separately in sequence or simultaneously or in separate master batches to be mixed later. In still another embodiment, the invention is a polyolefin resin composition having a mixture of a first component selected from talcs and a second component selected from feldspars, nephelines and nepheline syenites, wherein the ratio of the first component to the second component provides a abrasive property significantly lower than the expected law of mixtures. Another embodiment is a polyolefin film comprising the polyolefin resin composition having a ratio of the first component to the second component that provides a property of abrasivity significantly lower than that expected from the law of mixtures, and furthermore provides a significantly anti-blocking action. greater than any single component. Preferably, the composition of the polyolefin resin has a mixture of the first and second components wherein the ratio of the first component to the second component is about 1/3 to 3/1, and the abrasive property of the first and second components in the mixture it is about 80 percent or less than expected from the blending law and the first and second components in combination produce a degree of block formation of about 50 percent or less. In another embodiment, the invention is a polyolefin film comprising a first component selected from talcs and a second component selected from feldspar, nepheline and nepheline syenites, wherein the ratio of the first component to the second component provides a property of abrasivity significantly less than that of the second component. expected from the law of mixtures. Preferably, the polyolefin film comprises a first component selected from talcs and a second component selected from feldspars, nephelines and nepheline syenites, where the ratio of the first component to the second component provides a property of abrasivity significantly lower than that expected from the law of mixtures and wherein the ratio of the first component to the second component provides a significantly greater antiblocking action than with respect to any single component. The present invention is described in the following illustrative examples which do not intend to limit the scope of the invention.

EXAMPLES EXAMPLE 1 Laboratory measurements of the abrasivity of antiblocking agents were made using an Einlehner abrasion calibrator. Minerals and combinations of these were analyzed to determine their degree of abrasion compared to diatomaceous earth as a control. Talc samples A (Polytalc AG609), talc B (PolyBloc), nepheline syenite (Minex 7), and diatomaceous earth (Super Floss) were tested. Samples and mixtures are described as follows: Test 1 = 50/50 * mixture of talc A and nepheline syenite. Test 2 = 50/50 mixture of talc B and nepheline syenite. Test 3 = Mix 75/25 of talc A and nephronic sienite. Test 4 = Mix 25/75 of talc A and nepheline syenite.

Test 5 = 100% talc A. Test 6 = 100% nepheline syenite Test 7 = 100% diatomaceous earth * "50/50" means 50 percent by weight to 50 percent by weight. All samples were analyzed in an Einlehner Model AT-1000 tester as dry solid sludge of 10% minerals. The body of use was a brass wire sieve. The duration of the test was 100 minutes and / or 174,000 abrasion cycles. The results of the test represent the weight loss of the wire expressed in milligrams (mg). The results are provided in Table 1.

TABLE 1 TABLE 1 (CONTINUED) EXAMPLE 2 In this experiment, talc and nepheline syenite minerals, alone and in combinations, in conjunction with diatomaceous earth as a control, were mixed in PEBD resin (low density polyethylene) using a Leistritz double worm extruder with a total load 50% to produce anti-block master batches. The ratio of talc to nepheline syenite was varied from 0/100 to 100/0. The master batches were then left (mixed) with LDPE and a master batch of erucamide suspension, and blown to form a one millimeter thick film using a single worm blown film line to produce a final film formulation of 2000 ppm (parts per million) in total of antiblock ore and 750 ppm of erucamide suspension agent. The products of the film were then tested to determine the degree of block formation and the optical properties (turbidity and clarity) using the following procedures.

Test procedures: (1) Degree of block formation. The parallel plate method of ASTM D3354-74 was used to measure the degree of block formation. In the preparation of the samples, pieces of 20.32 cm X 20.32 cm of flat tubing were cut. The double film layer was separated, and was slowly passed over a grounded bar to remove the static charges, and then reattached so that the inner surfaces of the original bubble were in contact with each other. All films were conditioned under a top load of 0.0703 kg / cm2 for 24 hours using a recirculated forced air oven set at 40 ° C. The force required to separate these two layers was then determined and expressed in grams. (2) Turbidity This test was performed in accordance with ASTM D 1003. Turbidity is the percentage of transmitted light that is scattered as it passes through the film specimen. The lower the turbidity number, the better the optical property of the film that transmits the light. (3) Clarity A Zebedee CL-100 clarity meter was used for this test and operated according to the manufacturers procedure. Optical clarity is defined as the distinction of emphasizing that an object can be seen through a film. The higher the clarity number, the better the resolution of the object through the film. Specific anti-block minerals used for these samples were: Talc A (Polytalc AG609), talc B (Polybloc), nephrinic syenite (Minex 7), and diatomaceous earth (Super Floss) The results of the degree of block formation, turbidity and clarity for the samples of example 2 are in Table 2.

TABLE 2 Formulation: 2000 ppm of antiblock agent and 750 ppm suspension in LDPE film TABLE 2 (CONTINUED) EXAMPLE 3 In this additional experiment, the master antiblock batches described in Example 2 were left with PEBD resin and blown into a one millimeter thick film using a single worm blown film line to produce a final film formulation of 5500 ppm in total of mineral against the formation of blocks. The products of the film were then tested to determine the degree of block formation and the optical properties (turbidity and clarity) using the same test methods as described in example 2. The results of the degree of block formation, turbidity and clarity for the samples of example 3, are in table 3.

TABLE 3 Formulation: 5500 ppm of antiblock and without suspension in PEBD film Talc C is ABT Talc 2500

Claims (10)

NOVELTY OF THE INVENTION CLAIMS

1. A mixture of a first component selected from talcs and a second component selected from feldspar, nepheline and nepheline syenites, wherein the ratio of the first component to the second component provides a significantly lower abrasivity property than that expected from the law of mixtures.

2. A mixture according to claim 1, characterized in that the ratio of said first component to said second component is in the range of 3: 1 to 1: 3.

3. A mixture according to claim 2, characterized in that said ratio is from 45:55 to 3: 1.

4. The mixture according to claim 1, characterized in that the abrasive property is about 50% less than that expected from the law of mixtures.

5. An agent against the formation of blocks comprising a mixture according to any of the preceding claims, selected from talcs and a second component selected from feldspars, wherein the ratio of the first component to the second component provides an action against the Block formation significantly greater than any single component.

6. The agent according to claim 5, characterized in that the action against block formation produces a degree of block formation of about seventy-five percent or less than any single component. The agent according to claim 5, characterized in that the mixing of the first component and the second component does not cause a significant loss of optical properties when used in a polyolefin film. 8. A polyolefin resin composition comprising a mixture of a first component selected from talcs and a second component selected from feldspars, nephelines and nepheline sienites, according to any of the preceding claims. The polyolefin resin composition according to claim 8, characterized in that the ratio of the first component to the second component is about 1/3 to 3/1, and the abrasive property of the first and second components in the mixture is 80% or less than expected from the mixing law, and the first and second components in combination produce a degree of block formation of about 50% or less. 10. A polyolefin film comprising the polyolefin resin composition according to claim 8 or 9.