阅读说明：本技术 一种复合纸及其制备方法 (Composite paper and preparation method thereof ) 是由 赵红奎 赵宁 于 2019-11-07 设计创作，主要内容包括：本发明涉及造纸技术领域,尤其涉及一种复合纸及其制备方法。本发明提供的制备方法,包括以下步骤：提供纤维浆料和纳米纤维素浆料；按照下层为纤维层、上层为纳米纤维素层的顺序,将所述纤维浆料和纳米纤维素浆料依次进行抄造,得到复合纸。所述制备方法操作简便,绿色环保。根据实施例的记载,利用本发明所述的制备方法制备得到的复合纸的吸液速率为85～91cm/min,抗张指数为202.53～223.64N·m/g；较未添加CNF的纤维纸均有明显的提高。(The invention relates to the technical field of papermaking, in particular to composite paper and a preparation method thereof. The preparation method provided by the invention comprises the following steps: providing a fiber slurry and a nanocellulose slurry; and sequentially manufacturing the fiber pulp and the nano-cellulose pulp according to the sequence that the lower layer is a fiber layer and the upper layer is a nano-cellulose layer to obtain the composite paper. The preparation method is simple and convenient to operate and is green and environment-friendly. According to the description of the embodiment, the composite paper prepared by the preparation method has the liquid absorption rate of 85-91 cm/min and the tensile index of 202.53-223.64 N.m/g; compared with the fiber paper without CNF, the method has obvious improvement.)

1. The preparation method of the composite paper is characterized by comprising the following steps:

providing a fiber slurry and a nanocellulose slurry;

and sequentially manufacturing the fiber pulp and the nano-cellulose pulp according to the sequence that the lower layer is a fiber layer and the upper layer is a nano-cellulose layer to obtain the composite paper.

2. The method of claim 1, wherein the fiber slurry has a concentration of 0.2 wt% to 2 wt% and a freeness of 20 ° SR to 35 ° SR.

3. The method of claim 2, wherein the fiber slurry is prepared by a method comprising the steps of:

pulping or eliminating latent defibering fiber pulp raw materials to obtain fiber pulp with the dryness of 10-40%;

and diluting the fiber pulp with the dryness of 10-40% to obtain the fiber pulp.

4. A method of producing as claimed in claim 3, characterized in that the fibre pulp stock is softwood bleached kraft pulp stock or hardwood bleached kraft pulp stock.

5. The method of claim 1, wherein the concentration of the nanocellulose pulp is from 0.01 wt% to 0.5 wt%.

6. The method of claim 1, wherein the machine used for papermaking is a dynamic sheet former, a sheeter, or a paper machine.

7. The method of claim 6, wherein, when the machine used for making the sheet is a dynamic sheet former,

the wire speed of the dynamic sheet former was 1000 m/min.

8. The method of claim 7 wherein said dynamic sheet former has a pump speed of 800 r/min.

9. The composite paper prepared by the preparation method of any one of claims 1 to 8, which is characterized by comprising fibers and nanocellulose;

the mass percentage of the nano-cellulose in the composite paper is 2-50%.

Technical Field

The invention relates to the technical field of papermaking, in particular to composite paper and a preparation method thereof.

Background

In recent years, environmental problems are increasingly prominent, and nanocellulose (CNF) is widely used in the field of pulping and papermaking because of its excellent properties such as green environmental protection, good biodegradability, good biocompatibility, high mechanical strength, good dimensional stability, large specific surface area, and the like.

At present, the CNF is used in the paper making process of paper mainly by uniformly mixing the CNF in a fiber slurry to obtain a mixed slurry and then making the mixed slurry. In the process, the CNF is rich in abundant hydroxyl groups and can form hydrogen bonds with fibers, so that the tensile strength of the paper is enhanced; and simultaneously, the combination between fibers is increased, the bulk of the paper is reduced, and the gaps of the paper are reduced. The liquid absorption properties of paper are mainly determined by capillarity, which decreases with decreasing porosity of the paper, leading to a decrease in the liquid absorption properties of the paper.

Therefore, how to solve the above problems and improve the liquid absorption performance of papermaking have been the focus of research.

Disclosure of Invention

The invention aims to provide composite paper and a preparation method thereof, wherein the composite paper has better water absorption.

In order to achieve the above object, the present invention provides the following technical solutions:

the invention provides a preparation method of composite paper, which comprises the following steps:

providing a fiber slurry and a nanocellulose slurry;

and sequentially manufacturing the fiber pulp and the nano-cellulose pulp according to the sequence that the lower layer is a fiber layer and the upper layer is a nano-cellulose layer to obtain the composite paper.

Preferably, the concentration of the fiber slurry is 0.2 wt% -2 wt%, and the beating degree is 20 DEG SR-35 DEG SR.

Preferably, the preparation method of the fiber slurry comprises the following steps:

pulping or eliminating latent defibering fiber pulp raw materials to obtain fiber pulp with the dryness of 10-40%;

and diluting the fiber pulp with the dryness of 10-40% to obtain the fiber pulp.

Preferably, the fiber pulp raw material is a softwood bleached kraft pulp raw material or a hardwood bleached kraft pulp raw material.

Preferably, the concentration of the nano cellulose pulp is 0.01 wt% to 0.5 wt%.

Preferably, the machine used for papermaking is a dynamic sheet former, a sheet former or a paper machine.

Preferably, when the machine used for making the sheet is a dynamic sheet former,

the wire speed of the dynamic sheet former was 1000 m/min.

Preferably, the dynamic sheet former has a pump speed of 800 r/min.

The invention also provides the composite paper prepared by the preparation method in the technical scheme, which is characterized by comprising fibers and nano-cellulose;

the mass percentage of the nano-cellulose in the composite paper is 2-50%.

The invention provides a preparation method of composite paper, which comprises the following steps: providing a fiber slurry and a nanocellulose slurry; and sequentially manufacturing the fiber pulp and the nano-cellulose pulp according to the sequence that the lower layer is a fiber layer and the upper layer is a nano-cellulose layer to obtain the composite paper. The preparation method is simple and convenient to operate, and is green and environment-friendly; meanwhile, CNF is rich in abundant hydroxyl groups, and can form hydrogen bonds with fibers at a fiber interface, so that the tensile strength of paper is enhanced. On one hand, the porosity of the fiber layer is not changed by layered papermaking, and on the other hand, the CNF layer contains a large amount of hydrophilic hydroxyl groups, and the hydroxyl groups have high polarity and are easily combined with water with high dielectric constant, so that the liquid absorption rate of the fiber layer is improved, and the improvement of the whole liquid absorption performance of the paper is promoted. According to the description of the embodiment, the composite paper prepared by the preparation method has the liquid absorption rate of 85-91 cm/min and the tensile index of 202.53-223.64 N.m/g; compared with the fiber paper without CNF, the method has obvious improvement.

Detailed Description

The invention provides a preparation method of composite paper, which comprises the following steps:

providing a fiber slurry and a nanocellulose slurry;

and sequentially manufacturing the fiber pulp and the nano-cellulose pulp according to the sequence that the lower layer is a fiber layer and the upper layer is a nano-cellulose layer to obtain the composite paper.

In the present invention, all the raw material components are commercially available products well known to those skilled in the art unless otherwise specified.

The invention provides fiber pulp and nanocellulose pulp. In the present invention, the method for preparing the fiber slurry preferably includes the steps of:

pulping or eliminating latent defibering fiber pulp raw materials to obtain fiber pulp with the dryness of 10-40%;

and diluting the fiber pulp with the dryness of 10-40% to obtain the fiber pulp.

The invention carries on beating or latency disintegration to the fiber pulp raw material, gets the fiber pulp with dryness of 10% -40%; in the present invention, the fiber pulp raw material is preferably a softwood bleached kraft pulp raw material or a hardwood bleached kraft pulp raw material. The present invention is not limited to any particular kind of the softwood and hardwood, and any softwood or hardwood known to those skilled in the art may be used. In the present invention, the fiber pulp raw material is preferably a commercially available product well known to those skilled in the art.

The invention does not have any special limitation on the pulping or the latent defibering, and the process known by the technical personnel in the field is adopted to carry out the pulping and the drying degree of the obtained fiber pulp reaches 20-35 SR degrees and 10-40 percent.

After the fiber pulp with the dryness of 10-40% is obtained, the fiber pulp with the dryness of 10-40% is diluted to obtain the fiber pulp. The dilution is not subject to any particular limitation in the present invention, and may be carried out by a procedure well known to those skilled in the art.

In the present invention, the concentration of the fiber slurry is preferably 0.2 wt% to 2 wt%, more preferably 0.3 to 1.5 wt%, and most preferably 0.5 to 1.0 wt%. The freeness of the fiber slurry is preferably 20 ° SR to 35 ° SR, more preferably 22 ° SR to 30 ° SR, and most preferably 22 ° SR.

In the present invention, the concentration of the nanocellulose pulp is preferably 0.01 wt% to 0.5 wt%, more preferably 0.3 wt% to 0.5 wt%, most preferably 0.3 wt%. In the invention, the length of the nano-cellulose in the nano-cellulose pulp is preferably 2-7 μm, and the diameter is preferably 20-30 nm. The nanocellulose pulp is preferably obtained by diluting a nanocellulose suspension; the nanocellulose suspension is preferably a commercially available product well known to the person skilled in the art; the present invention is not limited to any particular dilution.

The preparation method also comprises the step of sequentially manufacturing the fiber pulp and the nano cellulose pulp according to the sequence that the lower layer is the fiber layer and the upper layer is the nano cellulose layer to obtain the composite paper.

In the present invention, the machine for papermaking is preferably a dynamic sheet former, a sheet former or a paper machine, more preferably a dynamic sheet former. When the machine used for making the sheet is a dynamic sheet former, the wire speed of the dynamic sheet former is preferably 1000m/min, and the pump speed of the dynamic sheet former is preferably 800 r/min.

In the present invention, when the machine for papermaking is preferably a sheet maker, the sheet maker is preferably: the sheet making device adopts a valve to control water feeding, a pneumatic valve to bubble and homogenize, manually homogenize and vacuumize to quickly evacuate paper moisture for forming. The present invention does not specifically limit the conditions of the above-described process, and the process may be carried out under conditions known to those skilled in the art.

In the present invention, when the machine used for the paper making is preferably a paper machine, the paper machine is required to be provided with a multi-layer forming headbox, the paper machine preferably has a wire speed of 1300m/min, and the paper machine preferably has a stock speed of 1100 m/min.

The invention also provides the composite paper prepared by the preparation method of the technical scheme, which comprises fibers and nanocellulose;

the mass percentage of the nano-cellulose in the composite paper is preferably 2-50%, and more preferably 10-15%.

The composite paper and the method for producing the same according to the present invention will be described in detail with reference to the following examples, which should not be construed as limiting the scope of the present invention.