JP2000336599A - Method for dipping at multi-stage - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for dipping a base material comprising a fiber structure with chemical agents, by which the functional substances can effectively be dipped in the whole layer of the fiber structure and in portions near to the surface layer to obtain the highly functional dipped product at a production cost whose enhance is minimized. SOLUTION: This method for dipping a base material comprising a fiber structure with a chemical agent comprises the first dipping process for dipping the inner portion of the base material and the secondary dipping process for dipping portions near to the surface layer of the base material without drying the first dipped material. Therein, the chemical agent dipped in the secondary dipping process is diffused in the base material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-stage impregnation method for impregnated materials, in which a fiber structure used as a packaging material is impregnated and modified.

[0002]

2. Description of the Related Art In recent years, environmental problems have become more serious, and containers and packaging materials have to be easily disposed of, and the demand for containers and packaging materials using recyclable materials or easy incineration has increased. Therefore, the increase of waste is a major social problem. There is a great social demand for the reduction and recycling of garbage, and in the packaging container market, instead of metal cans, glass bottles, plastic bottles, and wooden boxes, paper that can be lightly incinerated and recycled as recycled paper In many cases, a container mainly composed of is used.

[0003] Conventionally, paper boxes for snacks, multi-pack outer paper boxes for stacking and packaging individually packaged products such as seasonings and canned beer, paper boxes for food and beverages, outer paper boxes for small household appliances, powder compacts 2. Description of the Related Art As a packaging material for a paper box such as a paper box of a detergent container, a fiber structure made of paper, nonwoven fabric, and other composite materials is used.
Compared with plastic containers and metal containers, paper containers have lower strength of the paper material itself and are more easily deformed. Therefore, when used in a heavy-weight packaging container or in an environment where a large pressure or load is applied, the required container strength may not be able to be maintained satisfactorily. However, as a paper container excellent in easy disposability and recyclability, as the application field expands, higher strength physical properties and physical properties close to those of metal materials and plastic materials are required.

Conventionally, when considering the packaging design of a paper container which is a fiber structure, for example, a method of improving the strength as an example of the function of the paper as the base paper of the packaging material is as follows. Focusing on pulp fiber, which is one of the methods, a method of using base paper having a large basis weight of paper and having a large paper thickness, for example. (2) A method using virgin pulp having a large pulp fiber length or a pulp fiber raw material having a large fiber length, focusing on the components of the paper. (3) A method of laminating a polymer such as a polyethylene resin on the surface. (4) A method of forming a coat layer, an impregnated layer, and the like on the surface of the paper made by coating or the like. (5) A method for improving the strength of paper by adding a chemical containing a functional substance as a main component for improving the strength of the paper in the papermaking process and fixing the chemical to pulp. Etc. are widely and generally performed.

[0005] To make a base paper of a specific specification,
Considering the general paper manufacturing process, mass production is unavoidable, and the current situation is that mass production suppresses an increase in production cost. In the conventional internal prescription at the papermaking stage, it is not easy to produce a functionally impregnated paper in a small lot, and paper materials corresponding to functions required individually are rarely produced.

Therefore, the functions required of the paper material include strength and water repellency. Many of these functions include laminating a polymer such as polyethylene on the surface layer or hard resin or water repellency on the surface layer. A modification method in secondary processing of coating or impregnating a resin having been used has been performed.

In the method of imparting water repellency, a polymer layer such as polyethylene is laminated on the surface layer, or a rosin or a substance exhibiting water repellency is coated on the surface layer or the surface layer is impregnated. I have been. That is, the conventional impregnating method of modifying the formed paper later to provide the required function is only a modification technique that acts on the surface layer and near the surface layer of the paper.

For example, impregnated paper in which the surface layer of the paper and the vicinity of the surface layer have been modified with an impregnating agent exhibits strength physical properties and water repellency provided in the surface layer, but their functions have been improved by modifying the paper surface layer. Shows the property of staying in the part. For example, it is recognized that the impregnated paper obtained by impregnating the surface layer with a modifier that modifies water repellency has improved water repellency on the paper surface. When molded into a packaging container, the end face of the impregnated paper was not often exposed, and no water repelling effect was observed on the exposed end face.

[0009] The use of recycled paper pulp can also be used to compensate for the lost physical properties of the paper itself, such as strength and water resistance, or to provide additional functionality to virgin pulp base paper. A reforming method by a secondary processing in which a chemical is impregnated into the entire layer of paper has been performed.

[0010] Therefore, by impregnating the inside of the paper material, physical properties such as strength and water resistance can be imparted to the inside of the paper base material, but the same function as a metal or plastic container is required. In the container market, strength, water resistance, water repellency and other functions have not yet been fully satisfied.
There is also a problem that the cost is high.

[0011]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and is intended to effectively impregnate a functional material into all layers and a surface layer of a fibrous structure.
It is another object of the present invention to provide a multi-stage impregnation method that not only obtains a highly impregnated material but also minimizes the increase in manufacturing cost.

[0012]

Means for Solving the Problems The present invention solves the above problems, and the invention according to claim 1 is a method for impregnating an impregnated material for impregnating a substrate comprising a fibrous structure with an agent. A step of performing primary impregnation by impregnating the inside of the substrate, and a step of performing secondary impregnation near the surface layer of the substrate without drying after the step, the impregnating agent of the secondary impregnation step is applied to the inside of the substrate. This is a multi-stage impregnation method characterized by diffusing.

According to a second aspect of the present invention, in the multi-stage impregnation method according to the first aspect, the primary impregnation step is performed by a dipping method in which a substrate made of a fibrous structure is immersed in a chemical tank. This is a multi-stage impregnation method.

According to a third aspect of the present invention, in the multi-stage impregnation method according to the first aspect, the primary impregnation step comprises applying a prescribed amount to a substrate made of a fibrous structure, and then forming the fibrous structure. This is a multi-stage impregnation method characterized by being performed by a press-fit impregnation method by compressing and deforming a substrate.

According to a fourth aspect of the present invention, in the multi-stage impregnation method according to the first, second or third aspect, the secondary impregnation step is to impregnate a substrate impregnated with the primary impregnation with a prescribed amount of the impregnating agent. And a multistage impregnation method.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in more detail. The present invention makes it possible to impregnate and modify the surface layer and the vicinity of the surface layer in addition to impregnating and modifying the entire structure of the fibrous structure base material. The invention according to claim 1 is a method for impregnating an impregnated material in which a substrate made of a fibrous structure is impregnated with a drug, wherein a step of impregnating the inside of the substrate and performing primary impregnation is performed without drying after the step. The multi-stage impregnation method is characterized in that, as a step of performing secondary impregnation near the surface layer of the substrate, an impregnating agent in the secondary impregnation step is diffused into the inside of the substrate.

In the multistage impregnation method of the present invention, as a first step, in a method for producing an impregnated material in which a substrate made of a fiber structure is impregnated with a drug, primary impregnation for impregnating the inside of the fiber structure is performed. Do. The form of the primary impregnation method in which the impregnating liquid penetrates into the interior of the fibrous structure base material is a dipping method or a coating method in which the fibrous structure base material is immersed in the impregnating liquid tank. And then press-fit impregnation method for compressively deforming the fibrous structure base material. For the method of these primary impregnation steps,
In the present invention, any method can be selected as long as the impregnating liquid can penetrate into the fibrous structure base material, depending on the fibrous structure base material and the impregnating liquid used.

As a subsequent second step, the primary impregnation is
The secondary impregnation is performed immediately near the surface layer without drying the primary impregnated base material. At this stage, the primary impregnated material does not go through the drying step, and the impregnating liquid and its solvent or diluent are still contained in the fibrous structure. By performing the second impregnation on the primary impregnated material in this state, the impregnating liquid used for the second impregnation is diffused from the surface of the fibrous structure to the inside thereof by the impregnating liquid contained in the fibrous structure base material. be able to.

By adjusting the supply amount of the impregnating liquid, the liquid viscosity, and the liquid solid content in the secondary impregnating step, the region where the secondary impregnating liquid impregnates and diffuses into the primary impregnated material (the impregnated layer for the fibrous structure). Depth) is determined. Furthermore, the impregnating liquid used in the secondary impregnation step uses a solvent having a good affinity for the impregnating liquid used in the primary impregnation step. It is introduced and diffused into the structure substrate. Therefore, there is an effect that the diluting solvent of the secondary impregnation liquid can be greatly reduced, and the subsequent drying step can be completed only once.

As the fibrous structure substrate used in the multi-stage impregnation method of the present invention, paper is often used, and paperboard such as balls and kraft, or recycled paper is mainly used and paperboard on which kraft paper is disposed on the surface layer. A thick paperboard having a paper thickness of 300 μm or more is preferably used. It is also possible to use either paper made of 100% virgin pulp, recycled paper made from waste paper, or base paper made by laminating these papers in the paper making process. is there. In the multistage impregnation method of the present invention, the fibrous structure base material constituting the impregnated material is not limited to a material and a configuration.

As the impregnating liquid, a resin-based impregnating agent which strengthens the bonding of the fibers of the fibrous structure is preferably used in the primary impregnation step of introducing the fiber into the fibrous structure. The impregnating resin in the impregnated material acts by adhering to the joint between the fibers constituting the impregnated material, thereby strengthening the joint where the fibers constituting the impregnated material are entangled, and external stress acting on the impregnated material. The effect of preventing the fiber from being displaced when it is made is extremely large. As a result, the impregnated material produced by the method for producing an impregnated material of the present invention is improved in both rigidity and toughness as compared with the impregnated material produced by the conventional production method whose surface layer has been modified.

The impregnating liquid used in the secondary impregnation step may be a cross-linking accelerator capable of performing a cross-linking reaction with the primary impregnating liquid to further improve the strength, or a liquid having only the surface layer near the surface to achieve its effect. What gives a water-repellent function and a blocking prevention function is used.

As the impregnated resin, acryl, acrylate, acrylonitrile, a copolymer of styrene and butadiene, and a polysilane compound are preferably used. In the present invention, the material and structure of the impregnating agent disposed in the impregnated material are not limited.

According to a second aspect of the present invention, in the multi-stage impregnation method according to the first aspect, the primary impregnation step is performed by a dipping method in which a substrate made of a fibrous structure is immersed in a chemical tank. This is a multi-stage impregnation method.

In the present invention, the primary impregnation step has an object of supplying not only the resin component but also the dispersion solvent in the secondary impregnation step to the fibrous structure base material as the primary impregnation liquid. Therefore, it is preferable to uniformly introduce the functional resin component of the primary impregnation liquid and its solvent into the fibrous structure base material by using the dipping method. Furthermore, by supplying the primary impregnating liquid from both the front and back surfaces of the fibrous structure base material by the dipping method, it is possible to quickly introduce the primary impregnating liquid into the inside of the base material.

[0026] Immediately after the primary impregnation step by the dipping method, it is preferable to provide a step of adjusting the impregnating liquid excessively contained on the surface and inside of the fibrous structure. Examples of the method include a method of squeezing excess impregnating liquid between two rolls, a method of squeezing excess impregnating liquid between rolls around which a nonwoven fabric is wound, and a method of air surplus impregnating liquid floating on a substrate surface. Although any known means may be used, the method for removing the excess impregnating liquid is not limited in the present invention.

According to a third aspect of the present invention, in the multi-stage impregnation method according to the first aspect, the primary impregnation step comprises applying a prescribed amount to a substrate made of a fibrous structure, and then forming the fibrous structure. This is a multi-stage impregnation method characterized by being performed by a press-fit impregnation method by compressing and deforming a substrate.

In the primary impregnation step, more preferably, a required constant amount of the impregnating liquid is supplied to the fibrous structure. However, the present inventors apply and impregnate the fibrous structure base material with the required constant amount of the impregnating liquid. The present invention also provides a press-in impregnation method in which the impregnating substrate is compressed and deformed to diffuse the impregnating liquid into the interior of the fibrous structure. By using the press-in impregnation method as the primary impregnation step of the present invention, the primary impregnating liquid is supplied to the fibrous structure in a specified amount, so that the excess impregnating liquid discharged in the primary impregnation step can be eliminated.

According to a fourth aspect of the present invention, in the multi-stage impregnation method according to the first, second or third aspect, the secondary impregnation step is performed by applying and impregnating a predetermined amount of the impregnating agent on the base material impregnated with the primary impregnation. And a multistage impregnation method.

In the secondary impregnation step of supplying the impregnating liquid further to the fibrous structure base material impregnated with the primary impregnating liquid in the primary impregnating step, the interior of the fiber structure is modified with the primary impregnated substance, and the vicinity of the surface layer is further modified. It is modified by secondary impregnation.

As the primary impregnated material, an impregnating agent that modifies from the surface layer to the inside of the fibrous structure is used, but in the secondary impregnating step,
In some cases, it is only necessary to obtain a reforming effect near the surface layer. For example, in the primary impregnation step, the rigidity imparting agent is impregnated into the interior of the fiber structure, and then in the secondary impregnation step, a water repellency effect may be required. At this time, the surface water-repellent agent only needs to stay in the vicinity of the surface, and the surface layer may be impregnated with a predetermined amount of the impregnating agent.

[0032]

Examples of the present invention will be described below. <Example 1> Recycled paper made from waste paper as a raw material was used as a paper base material. The basis weight is 400 g / m2 and the thickness is about 0.6 mm. This base material was impregnated with a water-proofing agent as a primary impregnation step, and then impregnated with a stiffening agent as a secondary impregnation step without drying the base material.

<Comparative Example 1> The same paper base as that described in Example 1 was used. This base material is impregnated with the same water-proofing agent as in Example 1 in a dipping method as a primary impregnation step, passes through a drying step, and then in a secondary impregnation step, the same stiffening agent as in Example 1 is applied by a gravure coater. Impregnated.

The impregnated paper of Example 1 was provided with a waterproofing agent on all layers and a stiffening agent near the surface layer. The impregnated paper obtained in Example 1 exhibited water resistance over all layers and was found to have improved wet strength. In the dry state, the stiffening agent is impregnated at a depth of about 200 μm from the surface layer, and the folding yield value in the MD of the paper is about 450 gf.
/ 40mm width and about 350g of bending yield value of base paper
The rigidity was higher than the f / 40 mm width. Further, when the container was formed by processing the impregnated paper, it was found to be water-resistant and highly rigid.

The impregnated paper obtained in Comparative Example 1 was provided with a waterproofing agent in all layers and a stiffening agent only in the surface layer. The impregnated paper obtained in Comparative Example 1 exhibited water resistance over all layers and was found to have improved wet strength. In the dry state, the stiffening agent is impregnated only in the surface layer of about 50 μm, and the folding yield value in the MD of the paper is about 370 gf /
The width was 40 mm, and only a slight improvement over the bending yield value of the base paper was observed. Further processing of this impregnated paper to form a container revealed that although the water resistance was recognized, the rigidity was only about the same as that of the container formed from the base paper.

As can be seen from the above comparison, in the conventional impregnation method and the impregnation method using the coating method, it is difficult to adjust the depth (layer) of the impregnation layer in the secondary impregnation, and only a relatively shallow impregnated paper is obtained. I couldn't. However, the impregnated paper produced by the multi-stage impregnation method of Example 1 has a relatively large secondary impregnation layer, and its impregnation depth can be easily adjusted. And rigidity could be given.

[0037]

Since the present invention is configured as described above, the following effects can be obtained.

As a method of impregnating a substrate made of a fibrous structure such as paper or nonwoven fabric with an impregnant for impregnating a drug, primary impregnation is performed by impregnating the inside of the substrate, and without drying the primary impregnated substrate. Immediately after the secondary impregnation near the surface layer, the impregnating agent in the secondary impregnation step can diffuse into the substrate, easily imparting the desired multiple functions to the fibrous structure substrate and increasing the manufacturing cost Can be a multi-stage impregnation method that minimizes

Claims (4)

[Claims] 1. A method for impregnating a substrate comprising a fibrous structure with a drug, comprising the steps of: impregnating the interior of the substrate with a primary impregnation; and drying the substrate without drying after the step. A multi-stage impregnation method, wherein the step of performing secondary impregnation near the surface layer includes diffusing an impregnating agent in the secondary impregnation step into the inside of the substrate. 2. The multi-stage impregnation method according to claim 1, wherein
A multi-stage impregnation method, wherein the primary impregnation step is performed by a dipping method in which a substrate made of a fibrous structure is immersed in a chemical tank. 3. The multi-stage impregnation method according to claim 1, wherein
A multi-stage impregnation method, wherein the primary impregnation step is performed by a press-in impregnation method by applying a prescribed amount to a substrate made of a fiber structure and then compressing and deforming the substrate made of the fiber structure. 4. The multi-stage impregnation method according to claim 1, wherein the secondary impregnation step is performed by a coating method in which a predetermined amount of an impregnating agent is applied and impregnated on the primary impregnated substrate. Multi-stage impregnation method.