Use of sorbitol diacetal compositions

Abstract

The application discloses a use of a sorbitol diacetal composition. The application provides a use of a sorbitol diacetal composition in reducing the bubble content in a polyolefin resin, the composition comprising a first compound, a second compound, a third compound and a fourth compound; the first compound, the second compound, the third compound and the fourth compound are different sorbitol compounds; the total content of the first compound and the second compound is greater than or equal to 10 wt% and less than or equal to 90 wt%; the total content of the third compound and the fourth compound is greater than or equal to 10 wt%. The composition of the application can effectively reduce the bubble content in a polyolefin composition.

Description

[0001] This application is a divisional application of patent application No. 202411716015.8, filed on November 27, 2024, entitled “Use of Sorbitol Diacetal Compositions and Method for Preparing Polyolefin Compositions”. Technical Field

[0002] This invention relates to the use of a sorbitol diacetal composition. Background Technology

[0003] Polyolefin resins have become a class of polymer materials with large production volume and wide application due to their abundant raw materials, low price, easy processing and molding, and excellent comprehensive performance.

[0004] CN111825882A discloses a composition comprising a transparent nucleating agent, an inorganic pigment, and an organic pigment. The organic pigment is poorly soluble in water and organic solvents, and the inorganic pigment has a decomposition temperature greater than 250°C. All pigments are solid powders. This prior art uses a nucleating agent to improve brightness and gloss, resulting in polyolefin products with a higher content of air bubbles.

[0005] CN113121911A discloses a high-transparency polypropylene composition comprising the following components: isotactic polypropylene, a modified nucleating agent, an antioxidant, and a light stabilizer. The modified nucleating agent is composed of a hydroxyl-free sorbitol derivative and a sorbitol-based nucleating agent. The sorbitol-based nucleating agent is selected from one or more of 1,3:2,4-dibenzylsorbitol, 1,3:2,4-di(p-methylbenzyl)sorbitol, and 1,3:2,4-di(3,4-dimethylbenzyl)sorbitol. This polypropylene composition has a high bubble content after extrusion molding. Summary of the Invention

[0006] In view of this, the object of the present invention is to provide a use of a sorbitol diacetal composition that can reduce the bubble content in polyolefin resins.

[0007] This invention provides the use of a sorbitol diacetal composition in reducing the bubble content in polyolefin resins, the sorbitol diacetal composition comprising the following components:

[0008] (1) The first compound as shown in formula (I):

[0009]

[0010] R1 and R2 are each independently selected from C1 to C6 alkyl groups;

[0011] (2) The second compound as shown in formula (II):

[0012]

[0013] R3 to R6 are each independently selected from C1 to C6 alkyl groups;

[0014] (3) The third compound as shown in formula (III):

[0015]

[0016] R7 to R9 are each independently selected from C1 to C6 alkyl groups;

[0017] (4) The fourth compound as shown in formula (IV):

[0018]

[0019] Among them, R 10 ~R 12 Alkyl groups selected independently from C1 to C6;

[0020] The total content of the first and second compounds is greater than or equal to 10 wt% and less than or equal to 90 wt%; the total content of the third and fourth compounds is greater than or equal to 10 wt%.

[0021] According to the use of the present invention, preferably, R1 and R2 are independently selected from methyl, ethyl, propyl, butyl, pentyl and hexyl, respectively, wherein R1 is located at the para position of the benzene ring and R2 is located at the para position of the benzene ring;

[0022] R3 to R6 are each independently selected from methyl, ethyl, propyl, butyl, pentyl, and hexyl;

[0023] R7 to R9 are each independently selected from methyl, ethyl, propyl, butyl, pentyl, and hexyl;

[0024] R 10 ~R 12 Each of the following is independently selected from methyl, ethyl, propyl, butyl, pentyl, and hexyl.

[0025] According to the present invention, preferably, propyl is selected from n-propyl and isopropyl; butyl is selected from n-butyl, isobutyl, sec-butyl, and tert-butyl; pentyl is selected from n-pentyl, 2-methylbutyl, 3-methylbutyl, 1-ethylpropyl, 2-ethylpropyl, 2,3-dimethylpropyl, and 2,2-dimethylpropyl; and hexyl is selected from n-hexyl, 2-methylpentyl, 3-methylpentyl, 2,3-dimethylbutyl, and 2,2-dimethylbutyl.

[0026] According to the use of the invention, preferably, in the sorbitol diacetal composition, the total content of the third and fourth compounds is greater than or equal to 30 wt% and less than or equal to 70 wt%.

[0027] According to the use of the present invention, preferably, in the sorbitol diacetal composition, the mass ratio of the first compound and the second compound is 1:(0.3-8).

[0028] According to the present invention, preferably, the first compound is 1,3:2,4-di(4-methylbenzyl)-D-sorbitol, the second compound is 1,3:2,4-di(3,4-dimethylbenzyl)-D-sorbitol, and the third and fourth compounds are 1,3-p-methylbenzyl-2,4-(3,4-dimethylbenzyl)-D-sorbitol and 1,3-(3,4-dimethylbenzyl)-2,4-p-methylbenzyl-D-sorbitol, respectively.

[0029] According to the present invention, preferably, the amount of the sorbitol diacetal composition is 0.1 to 0.5 wt%, based on the mass of the polyolefin resin;

[0030] The polyolefin resin is selected from one or more of polyethylene, polypropylene, and polybutene.

[0031] According to the intended use of the invention, preferably, the method includes the following steps:

[0032] The raw materials comprising polyolefin resin and the sorbitol diacetal composition are granulated to obtain polyolefin resin particles, and the polyolefin resin particles are injection molded at 150-350°C to obtain a polyolefin composition.

[0033] According to the intended use of the invention, preferably, the method includes the following steps:

[0034] The raw materials comprising polyolefin resin and the sorbitol diacetal composition are extruded at 150–350°C to obtain the polyolefin composition.

[0035] According to the intended use of the invention, preferably, the raw material further includes ultramarine; the amount of ultramarine is 0.005 to 0.2 wt% based on the polyolefin resin.

[0036] The sorbitol diacetal composition of the present invention can reduce the generation of bubbles in polyolefin resins during processing and molding, and the resulting polyolefin composition does not contain bubbles. Detailed Implementation

[0037] The present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0038] <Uses to reduce air bubbles>

[0039] This invention provides the use of a sorbitol diacetal composition in reducing the air bubble content in polyolefin resins. The sorbitol diacetal composition comprises a first compound, a second compound, a third compound, and a fourth compound. In some embodiments, the sorbitol diacetal composition consists of the first compound, the second compound, the third compound, and the fourth compound. These air bubbles can be generated during the processing and molding of the polyolefin resin (e.g., injection molding, extrusion), that is, during the cooling and molding process of the molten polyolefin resin. Therefore, the "bubbles" of this invention are also referred to as "vacuum bubbles" or "hollow bubbles," which are substantially free of any gas.

[0040] The first compound of the present invention is shown in formula (I):

[0041]

[0042] R1 and R2 are each independently selected from C1 to C6 alkyl groups. Preferably, R1 and R2 are each independently selected from C1 to C3 alkyl groups. R1 and R2 can be each independently selected from methyl, ethyl, propyl, butyl, pentyl, and hexyl. Examples of propyl include, but are not limited to, n-propyl and isopropyl. Examples of butyl include, but are not limited to, n-butyl, isobutyl, sec-butyl, and tert-butyl. Examples of pentyl include, but are not limited to, n-pentyl, 2-methylbutyl, 3-methylbutyl, 1-ethylpropyl, 2-ethylpropyl, 2,3-dimethylpropyl, and 2,2-dimethylpropyl. Examples of hexyl include, but are not limited to, n-hexyl, 2-methylpentyl, 3-methylpentyl, 2,3-dimethylbutyl, and 2,2-dimethylbutyl. R1 and R2 can be the same or different. Preferably, R1 and R2 are the same. More preferably, R1 and R2 are both methyl.

[0043] R1 can substitute at the meta or para position of the benzene ring. Preferably, R1 is located at the para position of the benzene ring. R2 can substitute at the meta or para position of the benzene ring. Preferably, R2 is located at the para position of the benzene ring.

[0044] According to one embodiment of the present invention, the first compound is 1,3:2,4-bis(4-methylbenzyl)-D-sorbitol.

[0045] The second compound of the present invention is shown in formula (II):

[0046]

[0047] Wherein, R3 to R6 are each independently selected from C1 to C6 alkyl groups; preferably, R3 to R6 are each independently selected from C1 to C3 alkyl groups. R3 to R6 may be each independently selected from methyl, ethyl, propyl, butyl, pentyl, and hexyl. Examples of propyl include, but are not limited to, n-propyl and isopropyl. Examples of butyl include, but are not limited to, n-butyl, isobutyl, sec-butyl, and tert-butyl. Examples of pentyl include, but are not limited to, n-pentyl, 2-methylbutyl, 3-methylbutyl, 1-ethylpropyl, 2-ethylpropyl, 2,3-dimethylpropyl, and 2,2-dimethylpropyl. Examples of hexyl include, but are not limited to, n-hexyl, 2-methylpentyl, 3-methylpentyl, 2,3-dimethylbutyl, and 2,2-dimethylbutyl.

[0048] R3 to R6 can be the same or different. Preferably, R3 to R6 are the same. More preferably, R3 to R6 are all methyl groups.

[0049] According to one embodiment of the present invention, the second compound is 1,3:2,4-bis(3,4-dimethylbenzyl)-D-sorbitol.

[0050] In the composition of the present invention, the total content of the first compound and the second compound is greater than or equal to 10 wt% and less than or equal to 90 wt%.

[0051] In some embodiments, the total content of the first compound and the second compound is greater than or equal to 30 wt%. In other embodiments, the total content of the first compound and the second compound is greater than or equal to 50 wt%. In still other embodiments, the total content of the first compound and the second compound is greater than or equal to 60 wt%.

[0052] In some embodiments, the total content of the first compound and the second compound is less than or equal to 80 wt%. In some embodiments, the total content of the first compound and the second compound is less than or equal to 70 wt%. In other embodiments, the total content of the first compound and the second compound is less than or equal to 60 wt%. In still other embodiments, the total content of the first compound and the second compound is less than or equal to 50 wt%. In yet another embodiment, the total content of the first compound and the second compound is less than or equal to 40 wt%.

[0053] By controlling the contents of the first compound and the second compound within the above-mentioned range, the bubble content in the molded polyolefin resin composition can be effectively reduced.

[0054] The mass ratio of the first compound to the second compound can be 1:(0.3-8); preferably 1:(0.5-6); more preferably 1:(0.8-5); and most preferably 1:(0.9-1.2).

[0055] The third compound of the present invention is shown in formula (III):

[0056]

[0057] R7 to R9 are each independently selected from C1 to C6 alkyl groups. Preferably, R7 to R9 are each independently selected from C1 to C3 alkyl groups. R7 to R9 can be each independently selected from methyl, ethyl, propyl, butyl, pentyl, and hexyl. Examples of propyl include, but are not limited to, n-propyl and isopropyl. Examples of butyl include, but are not limited to, n-butyl, isobutyl, sec-butyl, and tert-butyl. Examples of pentyl include, but are not limited to, n-pentyl, 2-methylbutyl, 3-methylbutyl, 1-ethylpropyl, 2-ethylpropyl, 2,3-dimethylpropyl, and 2,2-dimethylpropyl. Examples of hexyl include, but are not limited to, n-hexyl, 2-methylpentyl, 3-methylpentyl, 2,3-dimethylbutyl, and 2,2-dimethylbutyl. R7 to R9 can be the same or different. Preferably, R7 to R9 are the same. More preferably, R7 to R9 are all methyl.

[0058] According to one embodiment of the present invention, the third compound is 1,3-p-methylbenzylidene-2,4-(3,4-dimethylbenzylidene)-D-sorbitol.

[0059] The fourth compound of the present invention is shown in formula (IV):

[0060]

[0061] Among them, R 10 ~R 12 Each alkyl group is independently selected from C1 to C6. Preferably, R 10 ~R 12 Alkyl groups, each independently selected from C1 to C3. R 10 ~R 12 It can be independently selected from methyl, ethyl, propyl, butyl, pentyl, and hexyl. Examples of propyl include, but are not limited to, n-propyl and isopropyl. Examples of butyl include, but are not limited to, n-butyl, isobutyl, sec-butyl, and tert-butyl. Examples of pentyl include, but are not limited to, n-pentyl, 2-methylbutyl, 3-methylbutyl, 1-ethylpropyl, 2-ethylpropyl, 2,3-dimethylpropyl, and 2,2-dimethylpropyl. Examples of hexyl include, but are not limited to, n-hexyl, 2-methylpentyl, 3-methylpentyl, 2,3-dimethylbutyl, and 2,2-dimethylbutyl. R 10 ~R 12 They can be the same or different. Preferably, R 10 ~R 12 Same. More preferably, R 10 ~R 12 All are methyl groups.

[0062] According to one embodiment of the present invention, the fourth compound is 1,3-(3,4-dimethylbenzyl)-2,4-p-methylbenzyl-D-sorbitol.

[0063] In the compositions of the present invention, the total content of the third and fourth compounds is greater than or equal to 10 wt%. In some embodiments, the total content of the third and fourth compounds is greater than or equal to 30 wt%. In other embodiments, the total content of the third and fourth compounds is greater than or equal to 40 wt%. In still other embodiments, the total content of the third and fourth compounds is greater than or equal to 45 wt%. In yet still other embodiments, the total content of the third and fourth compounds is greater than or equal to 50 wt%.

[0064] In some embodiments, the total content of the third and fourth compounds is less than or equal to 90 wt%. In some embodiments, the total content of the third and fourth compounds is less than or equal to 80 wt%. In other embodiments, the total content of the third and fourth compounds is less than or equal to 70 wt%. In still other embodiments, the total content of the third and fourth compounds is less than or equal to 60 wt%. In yet another embodiment, the total content of the third and fourth compounds is less than or equal to 50 wt%.

[0065] By controlling the contents of the third and fourth compounds within the above-mentioned range, the bubble content in the molded polyolefin resin composition can be effectively reduced.

[0066] The mass ratio of the third compound to the fourth compound is 1:(0.5 to 2); preferably 1:(0.8 to 1.5); more preferably 1:(0.9 to 1.2).

[0067] The composition of the present invention can reduce the bubbles generated during the processing of polyolefin resin, and the resulting polyolefin resin composition does not contain bubbles.

[0068] The polyolefin resin of this invention can be selected from one or more of polyethylene, polypropylene, and polybutene. Preferably, the polyolefin resin is polypropylene resin. The polypropylene resin can be isotactic polypropylene, atactic polypropylene, or syndiotactic polypropylene. Polypropylene has better compatibility with the composition of this invention and can better exert the effect of the composition.

[0069] Based on the mass of the polyolefin resin, the amount of the composition can be 0.1 to 0.5 wt%; preferably 0.15 to 0.4 wt%; more preferably 0.2 to 0.35 wt%.

[0070] <Preparation Method of Polyolefin Composition>

[0071] The method for preparing the polyolefin composition of the present invention includes the following steps: molding a raw material containing a sorbitol diacetate composition and a polyolefin resin to obtain the polyolefin composition. In some embodiments, the raw material may also contain one or more of pigments and antioxidants. The composition and amount of the sorbitol diacetate composition are as described above and will not be repeated here. Injection molding or extrusion molding processes can be used. The polyolefin composition prepared by the method of the present invention does not contain air bubbles and can obtain a polyolefin composition with low haze at low temperatures.

[0072] The pigments of this invention can be selected from one or more of quinacridone, perylene-based, dioxazine pigments, isoindolineone, pyrrolopyrroledione, phthalocyanine blue, and ultramarine blue.

[0073] Based on polyolefin resin, the amount of pigment can be 0.005-0.2 wt%; preferably 0.008-0.1 wt%; more preferably 0.01-0.05 wt%.

[0074] Injection molding

[0075] Injection molding includes a granulation step and an injection molding step. Specifically, the raw material comprising polyolefin resin and the above-mentioned sorbitol diacetal composition is granulated to obtain polyolefin resin particles; the polyolefin resin particles are then injection molded to obtain a polyolefin composition.

[0076] Raw materials comprising a polyolefin resin and a sorbitol diacetate composition can be mixed to obtain a mixture. The mixture is then melted, kneaded, and granulated. In some embodiments, the components of the composition need to be thoroughly mixed before the sorbitol diacetate composition is mixed with the polyolefin resin.

[0077] The granulation temperature can be between 150 and 350°C. In some embodiments, the granulation temperature is preferably between 200 and 300°C.

[0078] The injection temperature can be 150–350°C; preferably 170–300°C; more preferably 180–200°C.

[0079] Extrusion molding

[0080] A polyolefin composition is obtained by extruding a raw material comprising a polyolefin resin and a sorbitol diacetate composition at 150–350°C. Preferably, the raw material comprising the polyolefin resin and the sorbitol diacetate composition is extruded at 200–300°C.

[0081] <Applications for reducing haze and / or processing temperature>

[0082] This invention provides the use of a sorbitol diacetal composition in reducing haze and / or processing temperature in polyolefin resins. The composition comprises a first compound, a second compound, a third compound, and a fourth compound. In some embodiments, the composition consists of the first, second, third, and fourth compounds. The composition of this invention, when added to polyolefin resins, achieves good haze reduction over a wide range of processing temperatures. In particular, the composition of this invention, when added to polyolefin resins, achieves good haze reduction at lower processing temperatures. The processing temperature can be 150–350°C; preferably 170–300°C. In some embodiments, the processing temperature is 180–200°C. The processing temperature can be a molding processing temperature, such as injection molding temperature, extrusion temperature, etc.

[0083] The first compound of the present invention is shown in formula (I):

[0084]

[0085] R1 and R2 are each independently selected from C1 to C6 alkyl groups. Preferably, R1 and R2 are each independently selected from C1 to C3 alkyl groups. R1 and R2 can be each independently selected from methyl, ethyl, propyl, butyl, pentyl, and hexyl. Examples of propyl include, but are not limited to, n-propyl and isopropyl. Examples of butyl include, but are not limited to, n-butyl, isobutyl, sec-butyl, and tert-butyl. Examples of pentyl include, but are not limited to, n-pentyl, 2-methylbutyl, 3-methylbutyl, 1-ethylpropyl, 2-ethylpropyl, 2,3-dimethylpropyl, and 2,2-dimethylpropyl. Examples of hexyl include, but are not limited to, n-hexyl, 2-methylpentyl, 3-methylpentyl, 2,3-dimethylbutyl, and 2,2-dimethylbutyl. R1 and R2 can be the same or different. Preferably, R1 and R2 are the same. More preferably, R1 and R2 are both methyl.

[0086] R1 can substitute at the meta or para position of the benzene ring. Preferably, R1 is located at the para position of the benzene ring. R2 can substitute at the meta or para position of the benzene ring. Preferably, R2 is located at the para position of the benzene ring.

[0087] According to one embodiment of the present invention, the first compound is 1,3:2,4-bis(4-methylbenzyl)-D-sorbitol.

[0088] The second compound of the present invention is shown in formula (II):

[0089]

[0090] Wherein, R3 to R6 are each independently selected from C1 to C6 alkyl groups; preferably, R3 to R6 are each independently selected from C1 to C3 alkyl groups. R3 to R6 may be each independently selected from methyl, ethyl, propyl, butyl, pentyl, and hexyl. Examples of propyl include, but are not limited to, n-propyl and isopropyl. Examples of butyl include, but are not limited to, n-butyl, isobutyl, sec-butyl, and tert-butyl. Examples of pentyl include, but are not limited to, n-pentyl, 2-methylbutyl, 3-methylbutyl, 1-ethylpropyl, 2-ethylpropyl, 2,3-dimethylpropyl, and 2,2-dimethylpropyl. Examples of hexyl include, but are not limited to, n-hexyl, 2-methylpentyl, 3-methylpentyl, 2,3-dimethylbutyl, and 2,2-dimethylbutyl.

[0091] R3 to R6 can be the same or different. Preferably, R3 to R6 are the same. More preferably, R3 to R6 are all methyl groups.

[0092] According to one embodiment of the present invention, the second compound is 1,3:2,4-bis(3,4-dimethylbenzyl)-D-sorbitol.

[0093] In the composition of the present invention, the total content of the first compound and the second compound is greater than or equal to 10 wt% and less than or equal to 90 wt%.

[0094] In some embodiments, the total content of the first compound and the second compound is greater than or equal to 30 wt%. In other embodiments, the total content of the first compound and the second compound is greater than or equal to 50 wt%. In still other embodiments, the total content of the first compound and the second compound is greater than or equal to 60 wt%.

[0095] In some embodiments, the total content of the first compound and the second compound is less than or equal to 80 wt%. In some embodiments, the total content of the first compound and the second compound is less than or equal to 70 wt%. In other embodiments, the total content of the first compound and the second compound is less than or equal to 60 wt%. In still other embodiments, the total content of the first compound and the second compound is less than or equal to 50 wt%. In yet another embodiment, the total content of the first compound and the second compound is less than or equal to 40 wt%.

[0096] By controlling the contents of the first and second compounds within the above-mentioned range, the haze and processing temperature of the polyolefin resin can be effectively reduced.

[0097] The mass ratio of the first compound to the second compound can be 1:(0.3-8); preferably 1:(0.5-6); more preferably 1:(0.8-5); and most preferably 1:(0.9-1.2).

[0098] The third compound of the present invention is shown in formula (III):

[0099]

[0100] R7 to R9 are each independently selected from C1 to C6 alkyl groups. Preferably, R7 to R9 are each independently selected from C1 to C3 alkyl groups. R7 to R9 can be each independently selected from methyl, ethyl, propyl, butyl, pentyl, and hexyl. Examples of propyl include, but are not limited to, n-propyl and isopropyl. Examples of butyl include, but are not limited to, n-butyl, isobutyl, sec-butyl, and tert-butyl. Examples of pentyl include, but are not limited to, n-pentyl, 2-methylbutyl, 3-methylbutyl, 1-ethylpropyl, 2-ethylpropyl, 2,3-dimethylpropyl, and 2,2-dimethylpropyl. Examples of hexyl include, but are not limited to, n-hexyl, 2-methylpentyl, 3-methylpentyl, 2,3-dimethylbutyl, and 2,2-dimethylbutyl. R7 to R9 can be the same or different. Preferably, R7 to R9 are the same. More preferably, R7 to R9 are all methyl.

[0101] According to one embodiment of the present invention, the third compound is 1,3-p-methylbenzylidene-2,4-(3,4-dimethylbenzylidene)-D-sorbitol.

[0102] The fourth compound of the present invention is shown in formula (IV):

[0103]

[0104] Among them, R 10 ~R 12 Each alkyl group is independently selected from C1 to C6. Preferably, R 10 ~R 12 Alkyl groups, each independently selected from C1 to C3. R 10 ~R 12 It can be independently selected from methyl, ethyl, propyl, butyl, pentyl, and hexyl. Examples of propyl include, but are not limited to, n-propyl and isopropyl. Examples of butyl include, but are not limited to, n-butyl, isobutyl, sec-butyl, and tert-butyl. Examples of pentyl include, but are not limited to, n-pentyl, 2-methylbutyl, 3-methylbutyl, 1-ethylpropyl, 2-ethylpropyl, 2,3-dimethylpropyl, and 2,2-dimethylpropyl. Examples of hexyl include, but are not limited to, n-hexyl, 2-methylpentyl, 3-methylpentyl, 2,3-dimethylbutyl, and 2,2-dimethylbutyl. R 10 ~R 12 They can be the same or different. Preferably, R 10 ~R 12 Same. More preferably, R 10 ~R 12 All are methyl groups.

[0105] According to one embodiment of the present invention, the fourth compound is 1,3-(3,4-dimethylbenzyl)-2,4-p-methylbenzyl-D-sorbitol.

[0106] In the compositions of the present invention, the total content of the third and fourth compounds is greater than or equal to 10 wt%. In some embodiments, the total content of the third and fourth compounds is greater than or equal to 30 wt%. In other embodiments, the total content of the third and fourth compounds is greater than or equal to 40 wt%. In still other embodiments, the total content of the third and fourth compounds is greater than or equal to 45 wt%. In yet still other embodiments, the total content of the third and fourth compounds is greater than or equal to 50 wt%.

[0107] In some embodiments, the total content of the third and fourth compounds is less than or equal to 90 wt%. In some embodiments, the total content of the third and fourth compounds is less than or equal to 80 wt%. In other embodiments, the total content of the third and fourth compounds is less than or equal to 70 wt%. In still other embodiments, the total content of the third and fourth compounds is less than or equal to 60 wt%. In yet another embodiment, the total content of the third and fourth compounds is less than or equal to 50 wt%.

[0108] By controlling the content of the third and fourth compounds within the above range, the haze and processing temperature of polyolefin resins can be effectively reduced.

[0109] The mass ratio of the third compound to the fourth compound is 1:(0.5 to 2); preferably 1:(0.8 to 1.5); more preferably 1:(0.9 to 1.2).

[0110] The haze of the polyolefin composition of the present invention is less than or equal to 11%, preferably less than or equal to 10%, and more preferably less than or equal to 9.5%. In some embodiments, the haze is 3% to 11%, preferably 4% to 10%, and more preferably 8% to 9.5%. The haze is measured using a haze meter according to GB / T 2410-2008, and the sample is a thin sheet with a thickness of 1 mm.

[0111] The polyolefin resin of this invention can be selected from one or more of polyethylene, polypropylene, and polybutene. Preferably, the polyolefin resin is polypropylene resin. The polypropylene resin can be isotactic polypropylene, atactic polypropylene, or syndiotactic polypropylene. Polypropylene has better compatibility with the composition of this invention and can better exert the effect of the composition.

[0112] Based on the mass of the polyolefin resin, the amount of sorbitol diacetal composition can be 0.1-0.5 wt%; preferably 0.15-0.4 wt%; more preferably 0.2-0.35 wt%; and most preferably 0.2-0.3 wt%.

[0113] The raw materials are described below:

[0114] Polypropylene resin: MT20 powder produced by Sinopec Zhongyuan Petrochemical Co., Ltd., with a melt index of 18-22 g / 10 min and an ethylene content of less than 5%.

[0115] The testing method is described below:

[0116] Bubbles: The observation method is used. Observe whether the obtained polyolefin composition contains bubbles. If bubbles are present, mark it as "+"; if bubbles are absent, mark it as "-".

[0117] Haze: The haze was tested using a haze meter according to the method specified in GB / T 2410-2008. The sample was a thin film with a thickness of 1 mm.

[0118] Preparation Example 1

[0119] In a four-necked flask equipped with a stirrer, water separator, thermometer, and condenser, 10 g of sorbitol, 150 mL of cyclohexane, and 10 mL of methanol were added. While stirring slowly, 6.5 mL of p-tolualdehyde, 7.4 mL of 3,4-dimethylbenzaldehyde, and sulfuric acid as a catalyst were added. The reaction mixture was heated to reflux temperature in a constant-temperature water bath with rapid stirring and intermittent dropwise addition of methanol. After reacting for 6 hours, the pH of the reaction system was adjusted to 10 with NaOH / methanol solution. 150 mL of deionized water was added, and the mixture was distilled, filtered, washed with water until neutral, and dried to obtain a sorbitol diacetaldehyde composition.

[0120] The composition of the sorbitol diacetal was analyzed by HPLC-MS. It contained 25.5 wt% 1,3:2,4-di(4-methylbenzyl)-D-sorbitol, 49.3 wt% a mixture of 1,3-(3,4-dimethylbenzyl)-2,4-p-methylbenzyl-D-sorbitol and 1,3-p-methylbenzyl-2,4-(3,4-dimethylbenzyl)-D-sorbitol, and 25.2 wt% 1,3:2,4-di(3,4-dimethylbenzyl)-D-sorbitol.

[0121] Example 1

[0122] 0.2 parts by weight of the sorbitol diacetal composition obtained by the method of Preparation Example 1, 0.01 parts by weight of ultramarine blue, and 100 parts by weight of polypropylene resin were mixed evenly to obtain a mixture. The mixture was added to an extruder, and the extruder temperature was set to 240°C. The mixture melted in the extruder and flowed out from the extruder die. After being cooled with cold water, it was molded to obtain a polyolefin composition (a filament with a diameter of about 3-5 mm). The presence of air bubbles in the obtained polyolefin composition was observed, and the results are shown in Table 1.

[0123] Comparative Example 1

[0124] Except for replacing the sorbitol diacetal composition obtained by the method of Preparation Example 1 with 1,3:2,4-di(3,4-dimethylbenzyl)-D-sorbitol, the rest was the same as in Example 1. The presence or absence of air bubbles in the obtained polyolefin composition was observed, and the results are shown in Table 1.

[0125] Comparative Example 2

[0126] Except for replacing the sorbitol diacetal composition obtained by the method of Preparation Example 1 with 1,3:2,4-di(4-methylbenzyl)-D-sorbitol, the rest was the same as in Example 1. The presence or absence of air bubbles in the obtained polyolefin composition was observed, and the results are shown in Table 1.

[0127] Table 1

[0128] Serial Number Does it contain air bubbles? Example 1 — Comparative Example 1 + Comparative Example 2 +

[0129] Note: "—" indicates no air bubbles, and "+" indicates air bubbles.

[0130] As shown in Table 1, the sorbitol diacetal composition of the present invention can significantly reduce the content of bubbles in the polyolefin composition, and the resulting polyolefin composition contains no bubbles.

[0131] Examples 2-3 and Comparative Examples 3-8

[0132] 100 parts by weight of polypropylene resin, 0.2 parts by weight of additives (if any), and ultramarine blue (if any) are mixed evenly in a mixer to obtain a mixture. The mixture is melted and kneaded, and then granulated at 220°C to obtain polyolefin resin granules. The polyolefin resin granules are injection molded in an injection molding machine to obtain a polyolefin composition (a sheet with a thickness of 1 mm).

[0133] The selection of additives and the temperature of the injection molding machine are shown in Table 2, and the haze of the resulting polyolefin composition is shown in Table 2.

[0134] Table 2

[0135]

[0136] Note: "—" indicates that the ingredient is not added.

[0137] As shown in Table 2, the compositions of the present invention can effectively reduce the haze of polypropylene resin, especially the haze of polyolefin compositions obtained under low-temperature injection molding conditions. The haze can be reduced by more than 75%.

[0138] This invention is not limited to the above-described embodiments. Any modifications, improvements, or substitutions that can be conceived by those skilled in the art without departing from the essential content of this invention fall within the scope of this invention.

Claims

1. The use of a sorbitol diacetal composition in reducing the bubble content in polyolefin resins, characterized in that, The sorbitol diacetal compositions include 1,3:2,4-di(4-methylbenzyl)-D-sorbitol, 1,3:2,4-di(3,4-dimethylbenzyl)-D-sorbitol, 1,3-p-methylbenzyl-2,4-(3,4-dimethylbenzyl)-D-sorbitol and 1,3-(3,4-dimethylbenzyl)-2,4-p-methylbenzyl-D-sorbitol; In the sorbitol diacetal composition, the total content of 1,3:2,4-di(4-methylbenzyl)-D-sorbitol and 1,3:2,4-di(3,4-dimethylbenzyl)-D-sorbitol is greater than or equal to 50 wt% and less than or equal to 60 wt%, and the mass ratio of 1,3:2,4-di(4-methylbenzyl)-D-sorbitol and 1,3:2,4-di(3,4-dimethylbenzyl)-D-sorbitol is 1:(0.9~1.2); the total content of 1,3-p-methylbenzyl-2,4-(3,4-dimethylbenzyl)-D-sorbitol and 1,3-(3,4-dimethylbenzyl)-2,4-p-methylbenzyl-D-sorbitol is greater than or equal to 40 wt% and less than or equal to 50 wt%. Includes the following steps: The raw materials comprising polypropylene resin, the sorbitol diacetal composition, and ultramarine blue are extruded at 150–350°C to obtain a polypropylene resin composition; the haze of the polypropylene resin composition is 3–11%. Based on the mass of polypropylene resin, the amount of the sorbitol diacetal composition is 0.2–0.35 wt%. Based on the mass of polypropylene resin, the amount of ultramarine blue used is 0.01 to 0.05 wt%.

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