阅读说明：本技术 一种增强型醋酸纤维素透明复合薄膜的制备方法 (Preparation method of enhanced cellulose acetate transparent composite film ) 是由 袁正求 伍萍 陈雪梅 金灿 韩荣 陈柳 石顺存 周虎 于 2021-01-04 设计创作，主要内容包括：本发明公开了一种增强型醋酸纤维素透明复合薄膜的制备方法。本发明将醋酸纤维素粉、增塑剂,增透剂和溶剂在反应器中搅拌,再静置去泡,使醋酸纤维素粉末完全溶解在溶剂中,得到透明醋酸纤维素溶液；再将纳米金属氧化物或氢氧化物加入醋酸纤维素溶液中混合搅拌均匀,将所得的混合溶液涂布于模板上,在常温常压下通过干法转相技术成膜；将膜与模板剥离,即得到增强型醋酸纤维素透明复合薄膜产品。本发明制备的增强型生物质基透明复合薄膜,不仅推动了生物质资源高值化利用的研究进程,同时为解决传统的石油基塑料带来的“白色污染”等一系列环境问题开辟了新途径。(The invention discloses a preparation method of an enhanced cellulose acetate transparent composite film. Stirring cellulose acetate powder, a plasticizer, an anti-reflection agent and a solvent in a reactor, standing and defoaming to completely dissolve the cellulose acetate powder in the solvent to obtain a transparent cellulose acetate solution; adding the nano metal oxide or hydroxide into the cellulose acetate solution, mixing and stirring uniformly, coating the obtained mixed solution on a template, and forming a film at normal temperature and normal pressure by a dry phase inversion technology; and stripping the film from the template to obtain the enhanced cellulose acetate transparent composite film product. The enhanced biomass-based transparent composite film prepared by the invention not only promotes the research process of high-value utilization of biomass resources, but also opens up a new way for solving a series of environmental problems such as white pollution and the like caused by the traditional petroleum-based plastics.)

1. The preparation method of the enhanced cellulose acetate transparent composite film is characterized by comprising the following steps:

(1) stirring 10-20 parts by weight of cellulose acetate powder and 50-120 parts by weight of solvent in a reactor in a closed environment until a transparent cellulose acetate solution is formed, and then adding 1-3 parts by weight of plasticizer and 4-8 parts by weight of anti-reflection agent and uniformly stirring;

(2) adding 0.5-4.5 parts by weight of nano metal oxide or hydroxide particles into the solution obtained in the step (1), uniformly stirring to obtain a cellulose acetate mixed solution, and standing for defoaming;

(3) coating the cellulose acetate mixed solution obtained in the step (2) on a template by adopting a flow extension method, and forming a film by utilizing a dry phase inversion technology;

(4) and (3) stripping the film from the template, and cutting the film product into a proper size according to actual requirements to obtain the enhanced cellulose acetate transparent composite film.

2. The method of claim 1 wherein in step (1) the solvent is at least one of tetrahydrofuran and acetone.

3. The method of claim 1 wherein in step (1) the plasticizer is at least one of glycerol and ethylene glycol.

4. The method for preparing the enhanced cellulose acetate transparent composite film according to claim 1, wherein in the step (1), the anti-reflection agent is at least one of ethanol, propanol, butanol and pentanol.

5. The method for preparing the enhanced cellulose acetate transparent composite film according to claim 1, wherein in the step (2), the nano metal oxide or hydroxide is at least one of silicon oxide, aluminum oxide and aluminum hydroxide, and the particle size is 5-100 nm.

6. The method of claim 1 wherein in step (3) the solution is applied to a thickness of from 100 microns to 500 microns.

7. The method for preparing the reinforced cellulose acetate transparent composite film according to claim 1, wherein in the step (3), the conditions of the dry phase inversion technique are an air atmosphere or a nitrogen atmosphere, and the relative humidity of air is less than 60%.

8. The method of preparing a reinforced cellulose acetate transparent composite film according to claim 1, wherein in the step (3), the total thickness of the film is controlled to be 20 to 80 μm by adjusting the thickness of the cellulose acetate mixed solution coated on the template.

Technical Field

The invention relates to preparation of a transparent composite film, in particular to a preparation method of a biodegradable enhanced cellulose acetate transparent composite film.

Background

The fossil-based plastic has the characteristics of lightness, convenience and durability, and becomes an indispensable part of human social life. With the rapid development of human society, the consumption of fossil-based plastics is rapidly increased, but only a small part of plastics can be recycled, and most of plastics are discarded in nature or are incinerated, so that great harm is brought to natural ecology and human living environment. In order to better solve a series of problems of resource shortage and environmental pollution caused by fossil-based plastics, people begin to search for alternatives of fossil resources. Biomass is considered as a potential fossil substitute resource due to the characteristics of abundant resources, wide sources, renewability, biodegradation and the like. Cellulose biomass is a polysaccharide which is distributed most widely and has the largest content in nature, and a thermoplastic resin, namely cellulose acetate, can be obtained by performing anhydride esterification treatment on the cellulose biomass, wherein the cellulose acetate is the most widely used film-making raw material at present, and has the characteristics of low cost, stable property, excellent strength, good heat resistance, simple preparation process, wide raw material source and the like, so that the cellulose biomass is widely applied to the research fields of materials such as plastics, textiles, films, cigarette filters, packages, reverse osmosis membranes and the like. The strength of the cellulose acetate film is smaller than that of the fossil-based plastic film, the acting force among molecular chains of the cellulose acetate can be enhanced by adding the nano particles with hydroxyl groups, and the strength of the cellulose acetate film can be increased without affecting the transparency of the cellulose acetate film. Therefore, aiming at the defect that petroleum-based high polymer materials are difficult to degrade and the limitation of the existing cellulose acetate film forming process, the invention prepares the enhanced cellulose acetate transparent composite film with simple process, environmental friendliness, excellent performance and excellent strength by taking cellulose acetate as a raw material and compounding the cellulose acetate with nano metal (hydrogen) oxide.

Disclosure of Invention

In order to overcome the defects of the prior art and better solve a series of problems of energy shortage, environmental pollution and the like, the invention provides the preparation method of the enhanced cellulose acetate transparent composite film with simple process, environmental friendliness and excellent performance.

The invention aims to provide a preparation method of an enhanced cellulose acetate transparent composite film, which comprises the following steps:

(1) stirring 10-20 parts by weight of cellulose acetate powder and 50-120 parts by weight of solvent in a reactor in a closed environment until a transparent cellulose acetate solution is formed, and then adding 1-3 parts by weight of plasticizer and 4-8 parts by weight of anti-reflection agent and uniformly stirring;

(2) adding 0.5-4.5 parts by weight of nano metal oxide or metal hydroxide particles into the solution obtained in the step (1), uniformly stirring to obtain a cellulose acetate mixed solution, and standing for defoaming;

(3) coating the cellulose acetate mixed solution obtained in the step (2) on a template by adopting a flow extension method, and forming a film by utilizing a dry phase inversion technology;

(4) and (3) stripping the film from the template, and cutting the film product into a proper size according to the requirement to obtain the enhanced cellulose acetate transparent composite film.

Further, in the step (1), the solvent is at least one of tetrahydrofuran and acetone.

Further, in the step (1), the plasticizer is at least one of glycerol and ethylene glycol.

Further, in the step (1), the anti-reflection agent is at least one of ethanol, propanol, butanol and pentanol.

Further, in the step (2), the nano metal oxide or hydroxide is at least one of silicon oxide, aluminum oxide and aluminum hydroxide, and the particle size is 5-100 nm.

Further, in the step (3), the solution is coated to a thickness of 100 to 500. mu.m

Further, in the step (3), the dry phase inversion condition is an air atmosphere or a nitrogen atmosphere, and the relative humidity of air is less than 60%.

Further, in the step (3), the total thickness of the film is controlled to be 20 to 80 micrometers by adjusting the thickness of the cellulose acetate mixed solution coated on the template.

The enhanced cellulose acetate composite film product obtained by the invention is colorless and transparent in appearance, the light transmittance is more than 90.0%, the haze is 0.5-2.0%, the tensile strength is 80-140MPa, and the elongation is 5.0-15.0%.

Compared with the prior art for preparing petroleum-based packaging films, the invention has the following advantages and effects:

(1) the raw material used in the invention is cellulose acetate powder which is prepared by deriving renewable cellulose, and the raw material has wide source and low cost;

(2) the plasticizer and the anti-reflection agent with proper amount are used, so that the flexibility of the prepared film can be increased, and the transparency of the film is not influenced, thereby ensuring the strength, the flexibility and the transparency of the obtained film.

(3) The filler added in the invention is hydroxylated nano metal oxide or hydroxide which can form hydrogen bonds with unsubstituted hydroxyl on a cellulose acetate chain, thereby enhancing the interaction force among the cellulose acetate chains and achieving the purpose of improving the strength of the cellulose acetate film; in addition, the metal oxide or hydroxide is in nanometer level, so that light can be effectively diffracted without affecting the light transmittance of the film.

In a word, the enhanced biomass-based transparent composite film prepared by the invention not only promotes the research process of high-value utilization of biomass resources, but also opens up a new way for solving a series of environmental problems such as white pollution caused by the traditional petroleum-based plastics.

Drawings

FIG. 1 shows a photograph (left) of the appearance of the product obtained in example 1 and an electron microscope scan (right).

FIG. 2 shows a photograph (left) of the appearance of the product obtained in example 2 and an electron microscope scan (right).

FIG. 3 shows a photograph (left) of the appearance of the product obtained in example 3 and an electron microscope scan (right).

FIG. 4 shows a photograph (left) and an electron microscope scan (right) of the appearance of the product obtained in example 4.

FIG. 5 shows a photograph (left) and an electron microscope scan (right) of the appearance of the product obtained in example 5.

Detailed Description

The present invention will be described in further detail with reference to examples, but the embodiments of the present invention are not limited thereto.

Example 1

Placing 10 parts by weight of cellulose acetate powder and 50 parts by weight of tetrahydrofuran solvent into a sealed reactor, and stirring for 3 hours at normal temperature and normal pressure to completely dissolve the cellulose acetate powder in tetrahydrofuran; then adding 1 part by weight of glycerol and 4 parts by weight of ethanol and stirring to obtain a transparent solution; slowly adding 0.5 weight part of nano alumina into the transparent solution while stirring, uniformly mixing, and standing for 2 hours for defoaming. Coating the obtained mixed solution on a template by adopting a flow extension method, and forming a film by dry phase inversion in an air atmosphere under the environment of normal temperature and normal pressure and relative humidity of less than 60%; stripping the film from the template, and controlling the total thickness of the film to be 0.06mm by adjusting the thickness of the cellulose acetate solution coated on the template; and cutting the film product into a proper size according to the requirement to obtain the cellulose acetate transparent film product.

Example 2

Placing 20 parts by weight of cellulose acetate powder and 120 parts by weight of tetrahydrofuran solvent into a sealed reactor, and stirring for 3 hours at normal temperature and normal pressure to completely dissolve the cellulose acetate powder in the tetrahydrofuran; then adding 2 parts by weight of glycol and 6 parts by weight of propanol, and stirring to obtain a transparent solution; slowly adding 2.0 parts by weight of nano alumina into the transparent solution while stirring, uniformly mixing, and standing for 2 hours for defoaming. Coating the obtained mixed solution on a template by adopting a flow extension method, and forming a film by dry phase inversion in an air atmosphere under the environment of normal temperature and normal pressure and relative humidity of less than 60%; stripping the film from the template, and controlling the total thickness of the film to be 0.06mm by adjusting the thickness of the cellulose acetate solution coated on the template; and cutting the film product into a proper size according to the requirement to obtain the cellulose acetate transparent film product.

Example 3

Placing 10 parts by weight of cellulose acetate powder and 50 parts by weight of acetone solvent in a sealed reactor, and stirring for 3 hours at normal temperature and normal pressure to completely dissolve the cellulose acetate powder in acetone; then adding 1 weight part of glycerol and 4 weight parts of butanol, and stirring to obtain a transparent solution; slowly adding 1.5 parts by weight of nano aluminum hydroxide into the transparent solution while stirring, uniformly mixing, and standing for 2 hours for defoaming. Coating the obtained mixed solution on a template by adopting a flow extension method, and forming a film by dry phase inversion in an air atmosphere under the environment of normal temperature and normal pressure and relative humidity of less than 60%; stripping the film from the template, and controlling the total thickness of the film to be 0.04mm by adjusting the thickness of the cellulose acetate solution coated on the template; and cutting the film product into a proper size according to the requirement to obtain the cellulose acetate transparent film product.

Example 4

Placing 10 parts by weight of cellulose acetate powder and 80 parts by weight of tetrahydrofuran solvent into a sealed reactor, and stirring for 3 hours at normal temperature and normal pressure to completely dissolve the cellulose acetate powder in tetrahydrofuran; then adding 1 part by weight of glycerol and 6 parts by weight of amyl alcohol and stirring to obtain a transparent solution; slowly adding 3.0 parts by weight of nano alumina into the transparent solution while stirring, uniformly mixing, and standing for 2 hours for defoaming. Coating the obtained mixed solution on a template by adopting a flow extension method, and forming a film by dry phase inversion in an air atmosphere under the environment of normal temperature and normal pressure and relative humidity of less than 60%; stripping the film from the template, and controlling the total thickness of the film to be 0.04mm by adjusting the thickness of the cellulose acetate solution coated on the template; and cutting the film product into a proper size according to the requirement to obtain the cellulose acetate transparent film product.

Example 5

Placing 20 parts by weight of cellulose acetate powder and 160 parts by weight of tetrahydrofuran solvent into a sealed reactor, and stirring for 3 hours at normal temperature and normal pressure to completely dissolve the cellulose acetate powder in tetrahydrofuran; then adding 3 parts by weight of glycerol and 8 parts by weight of propanol and stirring to obtain a transparent solution; slowly adding 4.5 parts by weight of nano silicon oxide into the transparent solution while stirring, uniformly mixing, and standing for 2 hours for defoaming. Coating the obtained mixed solution on a template by adopting a flow extension method, and forming a film by dry phase inversion in an air atmosphere under the environment of normal temperature and normal pressure and relative humidity of less than 60%; stripping the film from the template, and controlling the total thickness of the film to be 0.02mm by adjusting the thickness of the cellulose acetate solution coated on the template; and cutting the film product into a proper size according to the requirement to obtain the cellulose acetate transparent film product.

The films prepared in examples 1 to 5 were subjected to electron microscope scanning using a Zeiss Sigma 300 instrument and to performance testing according to the following methods:

determination of tensile Strength and elongation at Break:

according to GB/T13022-1991, the film is cut into dumbbell-shaped strips with a knife, the width and thickness of the film are measured with a vernier caliper, the film is stretched at a speed of 300mm/min with a tensile tester, the tensile strength at break and the elongation at break of the film are recorded, and the test results are shown in Table 1.

Determination of transparency and haze:

the light transmittance and haze were measured at 650nm wavelength according to GB/T2410-2008 with a 721 spectrophotometer, the results of which are shown in Table 1.

Table 1:

case(s)	Tensile Strength (MPa)	Elongation at Break (%)	Light transmittance (%)	Haze (%)
					Example 1	131.16	14.8	90.2	1.85
Example 2	134.83	14.3	90.2	1.86
					Example 3	109.30	13.6	90.4	1.31
Example 4	104.02	12.5	90.4	1.23
					Example 5	81.27	6.9	91.1	0.58