阅读说明：本技术 一种基于大豆秸秆的完全可降解涂层纤维板制备方法 (Preparation method of completely degradable coating fiberboard based on soybean straws ) 是由 宋晓文 郭世杰 王秀仑 张艳锋 杜乐 何聪 国纪才 于 2021-09-15 设计创作，主要内容包括：本发明公开了一种基于大豆秸秆的完全可降解涂层纤维板制备方法,主要涉及植物纤维应用技术领域；包括步骤：S1、将大豆秸秆碎断,获得大豆秸秆小段；S2、对大豆秸秆小段进行浸润软化处理,获得软化的大豆秸秆小段；S3、对软化的大豆秸秆小段进行解离纤维化处理,获得秸秆纤维原液；S4、对秸秆纤维原液进行稀释,使纤维能够充分的润胀,获得完全润胀的秸秆纤维；S5、将完全润胀的秸秆纤维,注入到热压模具中,制备纤维板基体；S6、在纤维板基体表面涂压一层可降解防水材料；本发明能够获得无污染、可降解、具有优异防水防潮的效果的可降解涂层纤维板,尺寸稳定性高。(The invention discloses a preparation method of a completely degradable coating fiberboard based on soybean straws, and mainly relates to the technical field of plant fiber application; the method comprises the following steps: s1, cutting the soybean straw to obtain small sections of the soybean straw; s2, soaking and softening the soybean straw segments to obtain softened soybean straw segments; s3, performing dissociation and fibrosis treatment on the softened soybean straw small sections to obtain a straw fiber stock solution; s4, diluting the straw fiber stock solution to enable the fibers to be fully swollen, and obtaining fully swollen straw fibers; s5, injecting the completely swollen straw fibers into a hot-pressing mold to prepare a fiberboard substrate; s6, coating a layer of degradable waterproof material on the surface of the fiber board substrate; the invention can obtain the degradable coated fiberboard which is pollution-free and degradable and has excellent waterproof and moistureproof effects, and has high dimensional stability.)

1. A preparation method of a completely degradable coating fiberboard based on soybean straws is characterized by comprising the following steps:

s1, cutting the soybean straw to obtain small sections of the soybean straw;

s2, soaking and softening the soybean straw segments to obtain softened soybean straw segments;

s3, performing dissociation and fibrosis treatment on the softened soybean straw small sections to obtain a straw fiber stock solution;

s4, diluting the straw fiber stock solution to enable the fibers to be fully swollen, and obtaining fully swollen straw fibers;

s5, injecting the completely swollen straw fibers into a hot-pressing mold to prepare a fiberboard substrate;

s6, coating a layer of degradable waterproof material on the surface of the fiber board substrate.

2. The preparation method of the completely degradable coated fiberboard based on soybean straws as claimed in claim 1, wherein the method comprises the following steps: in the step S1, the soybean straw is the plant part left after the soybean fruit is obtained, including the root, stem and leaf, and pod shell.

3. The method for preparing the completely degradable coated fiberboard based on soybean straw as claimed in claim 1, wherein the dissociation fiberization process in step S3 is performed in a water circulation degradation system, the water circulation degradation system comprises a water tank, a straw degradation device capable of automatic feeding, and a water circulating pump, wherein a water inlet of the water circulating pump is communicated with a bottom end of the water tank, a water outlet of the water circulating pump is communicated with an inlet of the straw degradation device, an outlet of the straw degradation device is communicated with the water tank, and the straw degradation device and the water circulating pump are both controlled by a control panel.

4. The method for preparing the completely degradable coated fiberboard based on soybean straw as claimed in claim 3, wherein the specific steps of the step S3 are as follows: pouring a part of the softened soybean straw segments into a water tank, and injecting sufficient water into the water tank to smoothly circulate a solid-liquid mixture of the straws and the water, then starting a circulating water pump, starting the solid-liquid mixture of the straws and the water to circulate in the system, then starting a straw grinding device, enabling the distance between a bottom knife and a rotary knife of the straw grinding device to be the largest, starting the straw to be ground circularly, gradually adjusting a knife feeding button, gradually pouring the rest straw segments into the water tank until the straws are ground into fine fibers, finally opening a switch at the bottom of the water tank, enabling a fiber solution to pass through a 2mm sieve, removing a small amount of fibers which are not ground, obtaining a thick straw fiber stock solution, and containing the straw fiber stock solution in a bucket for later use.

5. The method for preparing the completely degradable coated fiberboard based on soybean straw as claimed in claim 1, wherein in the step S4, the ratio of straw fiber stock solution to water is 1: 9.

6. the method for preparing the completely degradable coated fiberboard based on soybean straws of claim 1, wherein the hot pressing parameters in the step S5 are as follows: the hot pressing temperature is 110-200 ℃, the applied pressure is 2-8MPa, and the hot pressing time is 30-120 min.

7. The method for preparing the completely degradable coated fiberboard based on soybean straws of claim 1, wherein in the step S6, after the degradable coating is attached to the surface and the side of the fiberboard substrate, a metal roller is used for the rolling process.

8. The method for preparing the completely degradable coated fiberboard based on soybean straws of claim 7, wherein the rolling pressure of the rolling process is 2MPa-3MPa, and the working speed is 3cm/s-4 cm/s.

9. The method for preparing the totally degradable coated fiberboard based on soybean straw as claimed in claim 7, wherein the fiberboard after the roll pressing treatment is subjected to a heat gun heating treatment.

10. The method for preparing the totally degradable coated fiberboard based on soybean straws as claimed in claim 1, wherein the degradable waterproof material comprises polylactic acid, polybutylene terephthalate-adipate and polyhydroxyalkanoates.

Technical Field

The invention relates to the technical field of plant fiber application, in particular to a preparation method of a completely degradable coating fiberboard based on soybean straws.

Background

The conventional fiber board is made by mechanically separating and chemically treating wood or plant fiber, adding adhesive and other additives, and hot-pressing. The product has the characteristics of smooth appearance, uniform texture, good processability and excellent mechanical property. However, the commonly used "trialdehyde glue" releases formaldehyde gas during use, causing damage to the environment and human health, and the glue is also a petroleum-based non-degradable product. The glue-free fiber board avoids the adverse effect of the formaldehyde gas, has excellent mechanical properties, but has greatly reduced waterproof performance, is easy to damp and mildew in a high-humidity environment, and affects the strength and the service life of the board.

The method for solving the problem of waterproofness of the fiber board, particularly the non-glue fiber board, mainly comprises two methods, one is to add a waterproof agent in the production process of the fiber board, the method can enable the whole board to be waterproof and moistureproof, but the addition of the waterproof agent can influence the combination performance of the fiber; the other is to treat the surface of the fiber board, for example, waterproof materials are sprayed or waterproof substances such as paraffin are coated on the surface, but the bonding capability of the paraffin and the fiber matrix is weak and the paraffin is easy to fall off; the sprayed waterproof material is complex in component, most of the sprayed waterproof material is also a petroleum-based product, the sprayed waterproof material is a non-degradable material, and the sprayed waterproof material only can be adhered to the surface of the fiberboard and cannot permeate into the fiberboard.

Disclosure of Invention

The invention aims to solve the problems in the prior art, and provides a preparation method of a completely degradable coated fiberboard based on soybean straws, which can obtain a degradable coated fiberboard which is pollution-free, degradable, waterproof and moistureproof and has high dimensional stability.

In order to achieve the purpose, the invention is realized by the following technical scheme:

a preparation method of a completely degradable coating fiberboard based on soybean straws comprises the following steps:

s1, cutting the soybean straw to obtain small sections of the soybean straw;

s2, soaking and softening the soybean straw segments to obtain softened soybean straw segments;

s3, performing dissociation and fibrosis treatment on the softened soybean straw small sections to obtain a straw fiber stock solution;

s4, diluting the straw fiber stock solution to enable the fibers to be fully swollen, and obtaining fully swollen straw fibers;

s5, injecting the completely swollen straw fibers into a hot-pressing mold to prepare a fiberboard substrate;

s6, coating a layer of degradable waterproof material on the surface of the fiber board substrate.

Preferably, in step S1, the soybean straw is the plant part left after the soybean fruit is obtained, including the root, stem and leaf, and pod shell.

Preferably, the defiberizing process in the step S3 is performed in a water circulation degradation system, the water circulation degradation system includes a water tank, a straw degradation device capable of automatically feeding, and a water circulating pump, a water inlet of the water circulating pump is communicated with a bottom end of the water tank, a water outlet of the water circulating pump is communicated with an inlet of the straw degradation device, an outlet of the straw degradation device is communicated with the water tank, and the straw degradation device and the water circulating pump are controlled by a control panel.

Preferably, the specific step of step S3 is: pouring a part of the softened soybean straw segments into a water tank, and injecting sufficient water into the water tank to smoothly circulate a solid-liquid mixture of the straws and the water, then starting a circulating water pump, starting the solid-liquid mixture of the straws and the water to circulate in the system, then starting a straw grinding device, enabling the distance between a bottom knife and a rotary knife of the straw grinding device to be the largest, starting the straw to be ground circularly, gradually adjusting a knife feeding button, gradually pouring the rest straw segments into the water tank until the straws are ground into fine fibers, finally opening a switch at the bottom of the water tank, enabling a fiber solution to pass through a 2mm sieve, removing a small amount of fibers which are not ground, obtaining a thick straw fiber stock solution, and containing the straw fiber stock solution in a bucket for later use.

Preferably, in the step S4, the ratio of the straw fiber stock solution to water is 1: 9.

preferably, the hot pressing parameters in step S5 are: the hot pressing temperature is 110-200 ℃, the applied pressure is 2-8MPa, and the hot pressing time is 30-120 min.

Preferably, in the step S6, after the degradable coating is attached to the surface and the side of the fiberboard substrate, a metal roller is used for performing a rolling process.

Preferably, the rolling pressure of the rolling treatment is 2MPa-3MPa, and the working speed is 3cm/s-4 cm/s.

Preferably, the heat gun heat treatment is performed on the fiber sheet after the roll pressing treatment.

Preferably, the degradable waterproof material comprises polylactic acid, polybutylene terephthalate-adipate and polyhydroxyalkanoate.

Compared with the prior art, the invention has the beneficial effects that:

the invention uses all the components of soybean straw, does not add any artificial synthetic resin, and adopts wet forming and mould pressing method to prepare the fiber board substrate, and then coats a layer of degradable waterproof material on the surface of the glue-free fiber board substrate, thereby preparing the degradable coated fiber board, which is pollution-free, degradable, has excellent waterproof and moistureproof effects, high stability, and improved mechanical strength and dimensional stability compared with the fiber board substrate without the coating, can meet the mechanical property requirement of JIS standard hard fiber board, and basically meets the requirement of dimensional stability.

Drawings

FIG. 1 is a process flow diagram of the present invention;

FIG. 2 is a schematic diagram of a water circuit degradation system;

FIG. 3 is test data for flexural strength of the present invention;

FIG. 4 is test data for water absorption of the present invention;

FIG. 5 is experimental data of the thickness expansion ratio of the present invention.

The reference numbers in the drawings:

1. a water tank; 2. a milling device; 3. a water circulating pump; 4. a control panel.

Detailed Description

The invention will be further illustrated with reference to the following specific examples. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Further, it should be understood that various changes or modifications of the present invention may be made by those skilled in the art after reading the teaching of the present invention, and these equivalents also fall within the scope of the present application.

Example (b): as shown in the attached figure 1, the invention relates to a preparation method of a completely degradable coating fiberboard based on soybean straws, which comprises the following steps:

s1, cutting the soybean straw to obtain small sections of the soybean straw; the main components of the soybean straws comprise cellulose, hemicellulose, lignin and trace crude protein, and after the soybean straws are obtained by adopting soybean fruits, the rest plant parts comprise roots, stems and leaves and bean husks.

S2, soaking and softening the soybean straw segments to obtain softened soybean straw segments, and soaking the soybean straw segments in a water tank for four days.

S3, performing dissociation and fibrosis treatment on the softened soybean straw small sections to obtain a straw fiber stock solution.

The defiberizing process is carried out in a water circulation grinding and defibering system, as shown in figure 2, the water circulation grinding and defibering system comprises a water tank 1, a straw grinding and defibering device 2 capable of feeding automatically and a water circulation pump 3, wherein a water inlet of the water circulation pump 3 is communicated with the bottom end of the water tank 1, a water outlet of the water circulation pump 3 is communicated with an inlet of the straw grinding and defibering device 2, an outlet of the straw grinding and defibering device 2 is communicated with the water tank 1, and the straw grinding and defibering device 2 and the water circulation pump 3 are controlled by a control panel 4.

The specific steps of the defibration treatment are as follows: pouring a part of the softened soybean straw segments into a water tank 1, and injecting sufficient water into the water tank 1 to enable a solid-liquid mixture of the straws and the water to smoothly circulate, then starting a circulating water pump 3, starting the solid-liquid mixture of the straws and the water to circulate in the system, then starting a straw grinding device 2, enabling the distance between a bottom knife and a rotary knife of the straw grinding device 2 to be the largest, starting the straws to be ground circularly, gradually adjusting a knife feeding button, gradually pouring the rest straw segments into the water tank until the straws are ground into fine fibers, finally opening a switch at the bottom of the water tank, enabling a fiber solution to pass through a 2mm sieve, removing a small amount of coarse fibers which are not ground, obtaining a straw fiber stock solution, and storing the straw fiber stock solution in a water bucket for later use. The grinding time of the straws is 20min-30min, and the length of the obtained straw fiber is less than 2 mm.

S4, diluting the straw fiber stock solution to enable the fibers to be fully swollen, and obtaining fully swollen straw fibers; the ratio of the straw fiber stock solution to water can be 1: 9.

s5, injecting the completely swollen straw fibers into a hot-pressing mold to prepare a fiberboard substrate, wherein the hot-pressing parameters are as follows: the hot pressing temperature is 110-200 ℃, the applied pressure is 2-8MPa, and the hot pressing time is 30-120 min, and further, the hot pressing temperature is 160 ℃, the applied pressure is 2-8MPa, and the hot pressing time is 30 min.

S6, coating a layer of degradable waterproof material on the surface of the fiber board substrate to improve the waterproofness.

The degradable waterproof material can adopt degradable environment-friendly plastics such as polylactic acid, polybutylene terephthalate-adipate, polyhydroxyalkanoate and the like and mixed materials thereof, and can also be other degradable waterproof environment-friendly materials.

Taking polylactic acid as an example, firstly heating and melting the polylactic acid at the melting temperature of 160-180 ℃, then attaching the molten polylactic acid to the surface and the side surface of the fiberboard substrate, and then performing rolling treatment by using a metal roller to obtain the coated fiberboard with a smooth surface. The implementation temperature of the adhesion process is determined according to the melting temperature of the degradable plastic, for example, the melting temperature of the polylactic acid is 160-180 ℃, which cannot be higher than the melting temperature, so as to avoid the decomposition of the polylactic acid. The fiberboard substrate may be completely immersed in the molten polylactic acid to ensure complete adhesion of the fiberboard substrate by the polylactic acid. After the fiber board is rolled by a metal roller, redundant polylactic acid is extruded out, the coated fiber board with uniform coating and smooth surface is obtained, meanwhile, the polylactic acid is partially infiltrated into the fiber board substrate, the rolling pressure is 2MPa-3MPa, and the working speed is 3cm/s-4 cm/s. And (3) carrying out heat treatment by a hot air gun on the side surface of the rolled coated fiberboard, removing redundant degradable plastics accumulated on the side surface after rolling, and simultaneously ensuring the uniform adhesion of the degradable plastics on the side surface and the uniform consistency of the degradable plastic coatings on the side surface and the surface.

The thickness of the degradable plastic coating is 0.2mm-0.5mm, and the specific thickness can be determined according to the application occasion of the coated fiberboard.

The mechanical property test and the dimensional stability test are carried out on the coated fiber board prepared by the embodiment, the test method and the standard are according to JIS A59052014, and various properties of the degradable coated fiber board and the fiber board substrate obtained by the embodiment are shown in figures 3-5, wherein the bending strength of the coated fiber board is 53-56MPa, the water absorption rate is 25.8% -36.0%, and the thickness expansion rate is 19.7% -25.5%, compared with the uncoated fiber board, the mechanical strength and the dimensional stability of the substrate are improved, and the degradable adhesive-free coated fiber board can meet the mechanical property requirement of a hard fiber board of the JIS standard and basically meets the requirement of the dimensional stability.