Oxidation pretreatment polyolefin and preparation process and application thereof

Abstract

The invention discloses polyolefin subjected to oxidation pretreatment as well as a preparation process and application of the polyolefin, and belongs to the technical field of new modified organic polymer materials. The polyolefin subjected to oxidation pretreatment has the following characteristics that the melt mass flow rate of the polyolefin subjected to oxidation pretreatment is improved compared with that before pretreatment. A composite material (plastic alloy) component used for modifying a polar material by a non-polar material and modified polyolefin with a better adhesive coating effect are prepared, and the application effect of the modified polyolefin is far better than that of unmodified polyolefin.

Description

Technical Field

[0001] The invention belongs to the technical field of modified organic polymer new materials, and specifically relates to an oxidative pretreated polyolefin and a preparation process and application thereof. Background Art

[0002] Polyolefins are a type of non-polar polymers. They are currently the most productive and widely used synthetic materials. The most representative of them are polypropylene and polyethylene. To date, their production capacity: polypropylene has exceeded 40 million tons / year, and polyethylene has exceeded 140 million tons / year.

[0003] Polyolefins are easily affected by light, heat, and oxidants. They are easily oxidized and degraded (such as polypropylene) or cross-linked (such as polyethylene) in the air, which is called "aging", which has a negative impact. Therefore, since the advent of polypropylene and polyethylene, scientific and technological workers have been working hard to solve the problem of anti-aging. And have achieved good results.

[0004] According to the research conclusions, the oxidation reaction of polypropylene, polyethylene, etc. is mainly a free radical reaction mechanism. Therefore, the oxidative grafting of polyolefins has become the main means of polyolefin modification. Since then, the oxidation of polyolefins has produced positive value. As far as polypropylene is concerned, oxidative degradation improves the melt fluidity of polypropylene and has been well utilized. For example, the addition of cooling masterbatch to the spinning of polypropylene uses organic peroxides to degrade the molecular chain of polypropylene and improve its fluidity in the molten state; melt-blown polypropylene also obtains its ultra-high fluidity in the molten state by adding organic peroxides. There are a lot of literature reports in this regard. And polyethylene is cross-linked by adding organic peroxides to improve its heat resistance and mechanical properties, which is also a mature technology. These are the positive utilization values ​​of the easy oxidation of polyolefins.

[0005] However, up to now, there has been no research report on the use of polyolefins pretreated with oxidants as modified components for the preparation of composite materials (plastic alloys) and adhesive coatings. Summary of the invention

[0006] In view of the above problems, the present invention provides an oxidatively pretreated polyolefin and its preparation process and application, and prepares a composite material (plastic alloy) component for modifying polar materials with non-polar materials, as well as a modified polyolefin with better adhesion and coating effect, and its application effect is far better than that of unmodified polyolefin.

[0007] To achieve the above object, the technical solution adopted by the present invention is:

[0008] An oxidatively pretreated polyolefin, the polyolefin is a homopolymer and / or copolymer of propylene, ethylene and butene, and the oxidatively pretreated polyolefin has the following characteristics: the melt mass flow rate of the oxidatively pretreated polyolefin is increased compared with that before pretreatment.

[0009] In a preferred implementation, the following steps are included:

[0010] (1) preparing an oxidation pretreatment liquid: mixing an oxidant, a pH adjuster, a co-solvent, a catalyst, and water in a reactor, and stirring the mixture to obtain an oxidation pretreatment liquid;

[0011] (2) Oxidative pretreatment of polyolefins: adding the polyolefin raw material to the oxidation pretreatment liquid reactor of step (1), rapidly heating to a reaction temperature of 60-95° C., and then stirring and reacting at normal pressure for 5-60 min, then stopping stirring, rapidly cooling to terminate the oxidation pretreatment reaction, and discharging and filtering, washing to neutrality, and drying to obtain an intermediate product;

[0012] (3) Product preparation: The intermediate product obtained in step (2) is added with an antioxidant and mixed evenly, wherein the amount of the antioxidant added is 0.1-0.5% of the mass of the intermediate product, and then granulated by screw melt extrusion at a melting temperature of 150-250° C. to obtain an oxidatively pretreated polyolefin product.

[0013] In a preferred embodiment, the oxidant in step (1) comprises an inorganic oxidant and an organic oxidant, wherein the inorganic oxidant is preferably potassium permanganate or hydrogen peroxide + catalyst, and the organic oxidant is preferably an organic peroxide.

[0014] In a preferred implementation, the total amount of the components oxidant, pH regulator, co-solvent and catalyst in the oxidation pretreatment liquid is controlled to be 0.2-4% of the total amount of the oxidation pretreatment liquid, the amount of the component oxidant is controlled to be 0.1-3.0% of the total amount of the pretreatment liquid, the total amount of the components pH regulator, co-solvent and catalyst is controlled to be 0.1-1.0% of the total amount of the pretreatment liquid, and the rest are water.

[0015] In a preferred implementation, the pH adjuster in step (1) is one of formic acid, acetic acid, hydrochloric acid and sulfuric acid, and the addition ratio is greater than 0 and less than or equal to 1.0% of the total amount of the oxidation pretreatment liquid.

[0016] In a preferred implementation, the co-solvent in step (1) is methanol or ethanol, and the co-solvent is only used in combination with hydrogen peroxide and organic peroxide, and the added ratio accounts for 0-1.0% of the total amount of the oxidation pretreatment liquid.

[0017] In a preferred implementation, the catalyst in step (1) is one of manganese dioxide, copper oxide, ferric chloride, catalase, vanadium pentoxide, 2-ethylanthraquinone, sodium tungstate, and molybdenum trioxide; the catalyst is preferably ferric chloride and 2-ethylanthraquinone, and the catalyst is only used in combination with hydrogen peroxide, and the addition ratio accounts for 0-0.2% of the total amount of the oxidation pretreatment liquid.

[0018] In a preferred implementation, in the step (2), the polyolefin raw material is selected from granular and powdery forms and added simultaneously, and the mass percentages thereof are 5-95% and 5-95% respectively.

[0019] In a preferred implementation, the solid-liquid mass ratio of the polyolefin and the oxidizing liquid in step (2) is 1:1-2.

[0020] An oxidant pretreated polyolefin is used as a modified component of a non-polar material to modify a polar material, such as a nylon / polyolefin composite material (nylon / polyolefin alloy) to replace untreated polyolefin, as well as a component of a coating and / or laminating material for plastic substrates such as woven bags and paper substrates, such as a component of a coating material for polypropylene woven bags composited with BOPP, a component of a coating material for polypropylene woven bags composited with kraft paper, and a component of a paper surface laminating material.

[0021] The existing technology is to mix polyolefin with a compatibilizer and a polar resin (such as nylon, etc.) to prepare a composite material with high impact resistance, and directly use it as a component of a coating material or a laminating material.

[0022] Compared with the prior art, the present invention has the following beneficial effects: when polyolefin is compounded with polar materials to prepare composite materials with high impact toughness, the pretreated polyolefin can be dispersed more ultrafinely than the untreated polyolefin, so better impact toughness can be obtained; because some components of the pretreated polyolefin have been oxidized, the oxidized parts have been polarized and are more easily adsorbed by the surface of polar materials (such as paper), so when the pretreated polyolefin material is used for coating materials and laminating materials, the adhesion is improved.

[0023] The present invention utilizes: 1. The difference in surface area between granular polyolefin and powdered polyolefin; 2. The characteristics that polyolefin does not absorb water and water cannot penetrate into the interior of the solid aggregate of polyolefin, etc., to keep the polyolefin in a solid state, with only the surface contacting the oxidant, thus controlling only part of the surface molecules to be oxidized. Also, due to the dispersion and isolation effect of water, it is difficult for the free radicals generated by the reaction to migrate from the surface of one particle to the surface of another particle, and it is difficult to produce crosslinking and deep oxidation. However, the natural oxidation rate of polyolefin is very slow, but by selecting different oxidants and compatibility, controlling the reaction temperature and reaction time, the oxidation can be accelerated and the degree of oxidation can be controlled, thereby achieving the purpose of effective oxidation pretreatment of polyolefin. DETAILED DESCRIPTION

[0024] In order to enable those skilled in the art to better understand the technical solution, the present invention is described in detail below in conjunction with embodiments. The description in this section is only exemplary and explanatory and should not have any limiting effect on the scope of protection of the present invention.

[0025] Embodiment 1:

[0026] A process for preparing oxidatively pretreated polyolefin comprises the following steps:

[0027] (1) Preparation of oxidation pretreatment solution: 23 kg of water, 10 g of ferric chloride, 50 g of acetic acid (chemically pure), 100 g of ethanol (95%), and 1000 g of hydrogen peroxide (30%) were added to an 80 L enamel reactor in sequence and stirred evenly;

[0028] (2) Oxidative pretreatment of polyolefins: 12 kg of polypropylene granules (model K7720, ethylene-containing copolymer) and 12 kg of polypropylene powder (model 230, propylene homopolymer) were added to the oxidation pretreatment liquid reactor of step (1), stirred evenly, and the temperature was rapidly raised to 80° C., and stirred under normal pressure for 10 min. Stirring was then stopped, and the pretreatment was terminated by rapid cooling. After the material was discharged, filtered, washed to neutrality, and dried, 24.02 kg of the intermediate product was obtained;

[0029] (3) 72 g of antioxidant 1010 was then added and the mixture was melt-extruded and granulated by a screw, with a melting temperature of 195° C. to obtain oxidized pretreated polypropylene, product number: PP300MO, and a melt flow rate of 31.7 g / 10 min (the melt flow rate of the mixed granulated material of the two polypropylenes that had not been oxidized was 22.9 g / 10 min).

[0030] Embodiment 2:

[0031] A process for preparing oxidatively pretreated polyolefin comprises the following steps:

[0032] (1) Preparation of oxidation pretreatment solution: Add 23.6 kg of distilled water to an 80 L enamel reactor, start stirring at 30 rpm, add 200 g of potassium permanganate and 100 g of acetic acid (chemically pure) respectively, and stir well;

[0033] (2) Oxidative pretreatment of polyolefins: Add 8 kg of polyethylene granules (model 2320) and 8 kg of polyethylene powder (model 7042, a copolymer containing a small amount of butene) to the oxidation pretreatment liquid reactor of step (1), stir evenly, quickly heat to 65° C., stir and react for 30 min, stop stirring, quickly cool and terminate the pretreatment, filter, wash to neutrality, and dry to obtain 16.01 kg of intermediate product;

[0034] (3) 50g of antioxidant 1010 was added and the mixture was melt extruded and granulated by screw. The oxidized pretreated polyethylene was obtained, with a melting temperature of 190°C, product number: PE100HO, and a melt flow rate of 10.3g / 10min (the melt flow rate of the mixed granulated material of the two polyethylenes without oxidation was 9.1g / 10min).

[0035] Embodiment 3:

[0036] A process for preparing oxidatively pretreated polyolefin comprises the following steps:

[0037] (1) Preparation of oxidation pretreatment solution: 33.5 kg of water, 5 g of molybdenum trioxide, 60 g of acetic acid (chemically pure), 50 g of ethanol (95%), and 500 g of hydrogen peroxide (30%) were added to a 100 L enamel reactor in sequence and stirred evenly;

[0038] (2) Oxidative pretreatment of polyolefins: Add 18 kg of polypropylene granules (model K7720) and 12 kg of polypropylene powder (model 230) to the oxidation pretreatment liquid reactor of step (1), stir evenly, quickly heat to 70° C., and react under normal pressure with stirring for 60 min. Then stop stirring, quickly cool to terminate the pretreatment, and filter, wash to neutrality, and dry to obtain an intermediate product; the intermediate product weighs 30.2 kg.

[0039] (3) 90 g of antioxidant 1010 was added and the mixture was melt-extruded and granulated by a screw. The melting temperature was 205° C. to obtain oxidized pretreated polypropylene. The product number was PP400MO. The melt flow rate was 42.7 g / 10 min (the melt flow rate of the mixed granulated material of the two polypropylenes that had not been oxidized was 22.9 g / 10 min).

[0040] Embodiment 4:

[0041] A process for preparing oxidatively pretreated polyolefin comprises the following steps:

[0042] (1) Preparation of oxidant pretreatment solution: 25 kg of water, 300 g of benzoyl peroxide, 100 g of ethanol (95%), and 20 g of formic acid were added to an 80 L enamel reactor in sequence and stirred evenly;

[0043] (2) Oxidative pretreatment of polyolefins: 12 kg of polypropylene granules (model K7726H, ethylene-containing copolymer) and 12 kg of polypropylene powder (model 230, propylene homopolymer) were added to the oxidation pretreatment liquid reactor of step (1), stirred evenly, and the temperature was rapidly raised to 85° C., and pretreatment was performed under normal pressure with stirring for 40 min, and then stirring was stopped, and pretreatment was terminated by rapid cooling. After the material was discharged, filtered, washed to neutrality, and dried, 24.03 kg of intermediate product was obtained;

[0044] (3) 72 g of antioxidant 1010 was then mixed in, and the mixture was melt-extruded and granulated by a screw, with a melting temperature of 198° C. to obtain pretreated polypropylene, product number: PP350MO, and a melt mass flow rate (melt index) of 34.9 g / 10 min (the melt mass flow rate (melt index) of the mixed granulated material of the two polypropylenes without pretreatment was 27.2 g / 10 min).

[0045] Application comparison test:

[0046] 1. Application of oxidative pretreated polypropylene: PP300MO: 10kg + homopolymer polypropylene PP-HH-280 (H2800): 10kg + LDPE 1C7A: 5kg are mixed evenly. The mixture is used as a composite coating material for polypropylene woven cloth and BOPP film. After the composite product, the tearing of BOPP film is destructive.

[0047] Comparison sample 1:

[0048] Homopolymer polypropylene PP-HH-280 (H2800): 20kg + LDPE1C7A: 5kg are mixed evenly, and the mixture is used as the composite coating material of polypropylene woven cloth and BOPP film. After the composite product, the BOPP film can be torn off in one piece.

[0049] The comparison of application effects shows that the bonding strength of the coating is greatly improved and the effect is better when the oxidized pretreated polypropylene partially replaces the traditional untreated polypropylene coating.

[0050] 2. Application of oxidative pretreated polyethylene: PE100HO: 5kg + maleic anhydride grafted PE2.5kg + PA6: 22.5kg mixed, melt extruded by twin screws for granulation, extrusion temperature: 245℃, no die expansion during extrusion. Sampling was made into standard specimens, and the test results were: impact strength: 36.7kJ / ㎡, elongation at break: 213%, tensile strength: 45.9MPa, flexural strength: 53.3MPa, flexural modulus: 1.79GPa.

[0051] Comparative sample 2: Polyethylene (7042): 2.5kg + Polyethylene (2320) 2.5kg + Maleic anhydride grafted PE: 2.5kg + PA6: 22.5kg were mixed and granulated by twin-screw melt extrusion. The extrusion temperature was 245°C. There was a slight die expansion phenomenon at the die mouth during the extrusion process. The samples were taken to make standard specimens. The tests showed: impact strength: 15.3kJ / ㎡, elongation at break: 59.2%, tensile strength: 39.3MPa, flexural strength: 51.2MPa, flexural modulus: 1.51GPa.

[0052] The comparison of application results shows that the nylon polyethylene composite material (nylon / polyethylene alloy) made by replacing untreated polyethylene with oxidized pretreated polyethylene has greatly improved impact toughness (from 15.3kJ / ㎡ to 36.7kJ / ㎡) and elongation at break (from 59.2% to 213%), which can be judged that the dispersion effect of oxidized pretreated polyethylene is better. Other mechanical properties are improved, and the overall modification effect is better.

[0053] It should be noted that, in this article, the terms: include, contain and any other variants are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. Specific examples are used in this article to illustrate the principle and implementation of the technical solution of the present invention. The above examples are only used to help understand the method of the present invention and its core idea. The above is only a preferred implementation of the present invention. It should be pointed out that due to the limitations of textual expression and the objective existence of infinite specific structures, for ordinary technicians in this technical field, without departing from the principle of the present invention, several improvements, modifications or changes can be made, and the above technical features can also be combined in an appropriate manner; these improvements, modifications, changes or combinations, or the direct application of the concept and technical solution of the present invention to other occasions without improvement, should be regarded as the protection scope of the present invention.

Claims

1. An oxidative pretreated polyolefin, characterized in that: The polyolefin is a homopolymer and / or copolymer of propylene, ethylene and butene, and the oxidatively pretreated polyolefin has the following characteristics: the melt mass flow rate of the oxidatively pretreated polyolefin is increased compared with that before pretreatment.

2. A process for preparing an oxidatively pretreated polyolefin according to claim 1, characterized in that: The following steps are involved: (1) preparing an oxidation pretreatment liquid: mixing an oxidant, a pH adjuster, a co-solvent, a catalyst, and water in a reactor, and stirring the mixture to obtain an oxidation pretreatment liquid; (2) Oxidative pretreatment of polyolefins: adding the polyolefin raw material to the oxidation pretreatment liquid reactor of step (1), rapidly heating to a reaction temperature of 60-95° C., and then stirring and reacting at normal pressure for 5-60 min, then stopping stirring, rapidly cooling to terminate the oxidation pretreatment reaction, and discharging and filtering, washing to neutrality, and drying to obtain an intermediate product; (3) Product preparation: The intermediate product obtained in step (2) is added with an antioxidant and mixed evenly, wherein the amount of the antioxidant added is 0.1-0.5% of the mass of the intermediate product, and then granulated by screw melt extrusion at a melting temperature of 150-250° C. to obtain an oxidatively pretreated polyolefin product.

3. The process for preparing an oxidatively pretreated polyolefin according to claim 2, characterized in that: The oxidant in step (1) includes an inorganic oxidant and an organic oxidant, wherein the inorganic oxidant is preferably potassium permanganate or hydrogen peroxide + catalyst, and the organic oxidant is preferably an organic peroxide.

4. The process for preparing an oxidatively pretreated polyolefin according to claim 3, characterized in that: The total amount of the components oxidant, pH regulator, co-solvent and catalyst in the oxidation pretreatment liquid is controlled to be 0.2-4% of the total amount of the oxidation pretreatment liquid, the amount of the component oxidant is controlled to be 0.1-3.0% of the total amount of the pretreatment liquid, the total amount of the components pH regulator, co-solvent and catalyst is controlled to be 0.1-1.0% of the total amount of the pretreatment liquid, and the rest are water.

5. The process for preparing an oxidatively pretreated polyolefin according to claim 2, characterized in that: In the step (1), the pH value adjusting agent is one of formic acid, acetic acid, hydrochloric acid and sulfuric acid, and the addition ratio is greater than 0 and less than or equal to 1.0% of the total amount of the oxidation pretreatment liquid.

6. The process for preparing an oxidatively pretreated polyolefin according to claim 4, characterized in that: In the step (1), the co-solvent is methanol or ethanol, and the co-solvent is only used in combination with hydrogen peroxide and organic peroxide, and the added proportion accounts for 0-1.0% of the total amount of the oxidation pretreatment liquid.

7. The process for preparing an oxidatively pretreated polyolefin according to claim 4, characterized in that: The catalyst in step (1) is one of manganese dioxide, copper oxide, ferric chloride, catalase, vanadium pentoxide, 2-ethylanthraquinone, sodium tungstate, and molybdenum trioxide; the catalyst is preferably ferric chloride and 2-ethylanthraquinone, and the catalyst is only used in combination with hydrogen peroxide, and the addition ratio accounts for 0-0.2% of the total amount of the oxidation pretreatment liquid.

8. The process for preparing an oxidatively pretreated polyolefin according to claim 2, characterized in that: In the step (2), the polyolefin raw material is selected from granular and powdery forms and added simultaneously, and the mass percentages thereof are 5-95% and 5-95% respectively.

9. The process for preparing an oxidatively pretreated polyolefin according to claim 6, characterized in that: In the step (2), the solid-liquid mass ratio of the polyolefin to the oxidizing liquid is 1:1-2.

10. The oxidatively pretreated polyolefin according to claim 1 is used as a modified component for modifying non-polar materials or polar materials, and a component of a coating material and / or a coating material for a woven bag plastic substrate or a paper substrate.