JPS6013823A - Continuous modification of surface of high polymer material - Google Patents

Abstract

PURPOSE:To modify continuously surface characteristics such as printability, coating performance, etc., by treating a flat high polymer material by corona discharge, coating it with a radically polymerizable monomer, covering it with a protecting material, grafting the surface by a redox polymerization reaction. CONSTITUTION:1 millijoule-10 joule/cm<2> energy is applied to one side of both sides of the flat high polymer material film a by the corona discharge treatment process [ I ] equipped with the corona discharge electrode 1 and the roll 2 for corona discharge treatment. It is then sent to the graft polymerization chamber 3 sealed with nitrogen, the high polymer material film a is coated with a solution of a monomer (e.g., acrylamide, etc.) containing a reducing agent (e.g., Na2S2O5- FeSO4, etc.) forming a redox catalyst from the feed opening 4 for the monomer, the film is then covered with the protecting film 5 such as polyolefinic resin film, etc., it is passed through the graft polymerization chamber 3 to carry out graft polymerization reaction, the protecting material is removed, and the film is passed through the washing bath 6, the drying chamber 7, and wound round the winder 8.

Description

Detailed Description of the Invention: Specifically, after corona discharge treatment is applied to the surface of a polymeric material film sheet or textile, the surface is treated with a radical polymerizable monomer under redox polymerization reaction pressure. This invention relates to a method for continuously modifying the surface of a polymeric material by copolymerization.

Polymer materials have good moldability, so they can be easily made into film, and this film has excellent characteristics in terms of transparency, water resistance, flexibility, and mechanical strength, and has a wide range of uses. It spans a wide range of fields. However, it has some properties that can be disadvantageous depending on its application, and surface properties are one of them. For example, hydrophobic polymer film does not lose its transparency due to clouding due to water vapor.
On the other hand, polymer material films with non-polar chemical structures have adhesive properties and
Printability, paintability. Problems may occur in antistatic properties, etc.

Up to now, many methods have been proposed to improve these defects on the surface of polymeric materials.

Broadly speaking, two methods are used.

One of them is kneading a modifier or the like into a polymer material before molding, such as surface modification by adding an antifogging agent or an antistatic agent. Another method is to modify the surface after molding, and there are many methods for this.

For example, applying a modifier to the surface of a polymer material, oxidation treatment,
Flame treatment, corona discharge treatment, and surface graft polymerization of different monomers have been attempted.

However, these methods are not necessarily satisfactory in terms of their effects, especially in terms of obtaining surface modification and luster effects without impairing the excellent properties of polymeric materials, sustainability of effects, and processing costs. The current situation is that this is not the case.

In the above-mentioned surface modification method by kneading antifogging agents and antistatic agents, it is necessary for an appropriate amount of the additive to seep into the surface of the polymer material, and if the amount of the additive is small, If the effect is small and excessive seepage occurs, transparency will decrease and surface gloss will be impaired. Furthermore, a fatal drawback of this method is that the amount of additive leached changes over time, or that the sustainability of its effect is greatly reduced by washing with water or the like.

On the other hand, among the surface modifications after molding, oxidation treatment, flame treatment,
Corona discharge treatment requires extremely harsh treatment conditions in order to be fully effective, which results in negative effects on the physical properties of the polymer base material itself, such as a decrease in strength and transparency. .

On the other hand, the surface graft polymerization method is attractive because it allows the desired function to be imparted relatively freely over a wide range of areas by selecting the type and amount of monomers suitable for the targeted surface modification. It can be said that there is a certain method. However, this method has not been put to practical use (there are only a few studies on fiber surface treatment using glow discharge or radiation irradiation grafting. This is because the processing cost is very high and practical use is not available at all stations.In addition, graft polymerization reactions using corona discharge treatment, which is a relatively inexpensive processing method, are also being considered (
Korea, Inha University Industry-Science and Technology Research Institute Paper Collection Volume 7
(February 1980, p. 99), this method involves removing impurities from the base polymer by solvent extraction, followed by harsh corona discharge treatment and high-temperature grafting reaction, and is far from the stage of practical application.

Among the surface treatment methods described above, the present inventors used the corona discharge treatment-graft polymerization method under mild conditions, which is relatively simple, and
As a result of extensive research into a practical graft polymerization method, the present invention was arrived at.

That is, in the present invention, the surface of a flat polymeric material is exposed to 1 millijoule/cm" to 1 millijoule/cm" by corona discharge in the atmosphere.
After applying energy of 0 di=-L/Cm', a redox catalyst is formed on the surface of the polymer material in a crab gas atmosphere.3! The process consists of applying a radically polymerizable monomer solution containing a base material, then proceeding with a birch graft polymerization reaction using a protective material, and then peeling off the protective material, washing, and drying. The present invention provides a method for continuously modifying the surface of a polymeric material, which is carried out while moving the polymeric material continuously or semi-continuously.

The polymeric material used in the present invention is one that can generate peroxide capable of initiating graft polymerization by corona discharge treatment. For example, low density polyethylene,
High-density polyethylene, ethylene-vinyl acetate copolymer,
Examples include polypropylene, polypropylene copolymer, polyvinyl chloride, polybutadiene, and the like. Specifically, these are in the form of film sheets, fabrics, etc., and are movable and have an appropriate length.

For the corona discharge treatment of the present invention, a continuous treatment device consisting of an electrode and a treatment roller, which is normally used industrially for imparting printability, is used.

Optimal processing conditions for corona discharge vary depending on material type, thickness and processing speed, but the applied energy is approximately in the range of 1 mmG-10 joules per cm'' of film surface area.

The radically polymerizable monomer used in the present invention is selected depending on the intended use and is not particularly limited. For example, acrylamide, 2-acrylamide-2-
Acrylamide compounds such as methylpropanesulfonic acid, styrene, styrene compounds such as sodium p-styrene sulfonate, acrylic acid, acrylic acid compounds such as methyl acrylate, maleic anhydride, maleic acid compounds such as dimethyl maleate, diallylamine, allyl alcohol, etc. Examples of monomers used for hydrophilic modification include acrylamide and sodium p-styrene sulfonate.

It is preferable to use acrylic acid or the like.

Graft polymerization in the present invention is initiated by decomposing peroxide generated on the surface of the polymeric material by corona discharge treatment using a reducing agent to generate radicals.

The reducing agent to be used is not particularly limited as long as it is used as a redox initiator, but the polymerization reaction may be carried out in a state where it is easily affected by impurities, such as when a small amount of monomer is applied to the surface of a polymeric material. When carrying out the reaction, it is desirable to use a highly effective reducing agent in excess.

For example, when using a reducing agent containing metaacidic sodium sulfite/ferrous sulfate, the amount is 0.5 to 20 mmol/2 x 10-4 to 8xlO- per 100f of monomer bath liquid.
It is desirable to add j mmol.

The graft reaction in the present invention is a redox room temperature reaction, and has the advantage that even if the polymer material used has a low softening temperature and is not heat resistant, it can be surface treated. Furthermore, since a water bath solution can be used as the monomer solution, this method is very advantageous from the viewpoint of handling and cost.

The processing speed in the method of continuously modifying the surface of a polymeric material by corona discharge treatment/graft polymerization reaction of the present invention depends on the reactivity of the polymeric material and the monomer and the target amount of grafting. Although it varies depending on the process and the size of the equipment, the processing speed is 2.
~60m/m1n is desirable.

The use of a protective material is essential to prevent uneven adhesion of the monomer solution due to the hydrophobicity of the surface of the polymeric material and to enable uniform surface treatment.

As the protective material, polyolefin resin, polyvinyl chloride resin, etc. can be used, and the protective material is not particularly limited to 1tilJ.

As a protective material, a film, a net, or a net-like material is used. These are used depending on the treatment method in the graft polymerization step, and both are used to ensure the attachment of the monomer bath liquid. That is, in the polymerization process, after the monomer solution is applied to the polymer material, the surface of the polymer material is not pressurized until the reaction is completed.
If sufficient monomer solution can be held, it can be used by simply stacking film-like adhesives, or by applying the monomer to the polymeric material and rolling it in before the reaction is completed. When winding pressure is applied by employing a polymerization process, a net-like protective material is used to maintain a constant amount of the monomer solution even after the pressure is applied. In addition, in the case of the wrapping method using this net-like protective material, it is possible to treat both sides of the polymeric material with one sheet of the net-like protective material.

Hereinafter, two aspects of the surface graft polymerization method of the present invention will be explained in detail using figures.

FIG. 1 shows the corona discharge treatment process mark, the graft polymerization process beating and washing process I, the finishing process consisting of the top of the drying process, and the winding machine depression.

The raw material film (a) is a corona discharge electrode (
One side or both sides are subjected to corona discharge treatment using a corona discharge treatment step comprising a corona discharge treatment roll (2) and a corona discharge treatment roll (2). Next, the monomer solution containing a reducing agent is sent to the nitrogen-sealed graft polymerization chamber (3), and the monomer solution containing a reducing agent is applied to the polymer material film (a) through the monomer supply port (4). It is covered with a protective film (5) such as a film, and transferred to a graft polymerization step 1 in which a monomer solution layer is formed into a polymeric material film (a).

As described above, the installation of the protective film (5) is extremely effective in preventing uneven adhesion of the monomer solution due to the hydrophobicity of the surface of the polymeric material and in enabling uniform surface treatment.

The reaction in this graft polymerization step proceeds while passing through the graft polymerization chamber (3). Therefore, the homopolymer produced as a by-product does not accumulate in the monomer solution, and the monomer having a constant viscosity can be supplied and the graft polymerization can proceed under constant conditions. The completion of the graft polymerization reaction varies depending on the target graft polymer and the reactivity of the polymer material film used with the monomer, but when a hydrophilic monomer is graft polymerized, water wets out within 50 seconds of the reaction. Products with good properties can also be obtained. Therefore, in this case, if the length of the graft polymerization chamber is 2 m, the processing speed is 4 l'm i
It is possible to increase the number up to n.

The treated film that has left the graft polymerization chamber (3) is sent to a cleaning tank (61) for a cleaning process, where the protective film (5) is peeled off and the surface of the treated film is cleaned.

After the washed treated film passes through a drying chamber (7), it is wound up by a winding machine (8) to complete the surface treatment by graft polymerization.

FIG. 2 shows an embodiment separated into a first step consisting of a corona discharge treatment step mark and a graft polymerization step 1, a second step consisting of a washing step 1, a drying step and a winding machine recess.

This embodiment is an effective means when increasing the amount of grafting or when using a polymeric material film or monomer with poor reactivity.

In the first step, first, the raw polymer material film (a) is subjected to corona discharge treatment on one or both sides using a corona discharge treatment process mark comprising a corona discharge electrode (1) and a corona discharge treatment roll (2). After that, it is sent to a graft polymerization chamber (3) sealed with nitrogen. Here, a monomer solution to which a reducing agent has been added is applied from the monomer supply port (4), a net-like protective material (glossy) is inserted, and the film is wound up using a winding machine OG. This allows the monomer bath solution to come into uniform contact with the film surface. The reaction is completed by leaving it as it is for the required time, and then the second step of washing and drying and winding is carried out in this order to complete the surface treatment.

The advantages of this semi-continuous method consisting of two steps are:
The advantage is that sufficient reaction time can be taken, so the desired treatment effect can be obtained without straining the polymerization process, and in terms of equipment, only one piece of net-like protective material is required for treatment on both sides. be.

The surface treatment method of the present invention can be selectively used depending on the purpose of treatment and the level of demand, and each treatment can be performed continuously or semi-continuously as appropriate to perform more effective surface treatment.

Hereinafter, the surface treatment effect by the method of the present invention will be explained with reference to Examples, but the present invention is not limited thereto. The surface treatment effect was evaluated based on the contact angle with water. The contact angle was measured using a goniometer type contact angle measuring device manufactured by Elma Optical ■.

Example 1 Low density polyethylene film (density α925° width 25cm
m, thickness 10 μm) was surface-treated at a processing speed of 2 m/min using the processing apparatus shown in FIG. 2 without pretreatment. The corona discharge treatment device is manufactured by Kasuga Denki ■, hard (oscillator:
HF5S-101, frequency H3DKHz, output voltage:
34 KV maximum, output type Kani IKIF, electrode shape: knife shape, length 3Qcm) was used.

The corona discharge treatment conditions were such that the gap between the electrode and the treatment roll was 19
111@W, ambient air, collector current 3A.

Continuous processing was performed under the condition of output power of 250W. The energy applied by corona discharge treatment was 2.5 di, Neel/cTn.
It is 2. ``The corona discharge-treated film was sent into a nitrogen-sealed graft polymerization chamber, and a monomer solution was applied thereto. As a monomer solution, sodium metaacid sulfite (Na, s) was added as a reducing agent to a 20% aqueous solution of acrylamide.
, o, ) / ferrous sulfate (FeSO4@7 H,O
) to 100 f of water bath solution at 2 mmol/1.4 x 1
0-' mmol was used.

At the same time as applying the monomer solution, a net-like preservation material (thickness 50μm9) was applied.
It was wound up with a gap of 1.5 mjr□, a mesh made of polyvinyl chloride resin sandwiched therebetween, and left to react at room temperature for 2 hours.

Next, the protective material was peeled off from the low-density polyethylene film, and then taken out and washed in water to obtain a surface-treated film. The obtained film has good water wettability,
The contact angle with water was 24 degrees. Note that the raw material low-density polyethylene has no hydrophilicity at all and has a contact angle with water of 80 degrees, which clearly demonstrates the effect of the surface graft polymerization of the present invention.

Example 2 Low density polyethylene film (density 0.925° width 25
cm, thickness 100 μm) was surface-treated at a processing speed of 2 rnAnin using the processing apparatus shown in FIG. 1 without pretreatment. The corona discharge treatment equipment and corona discharge treatment conditions used were as in Example 1.

The corona discharge-treated film was introduced into a nitrogen-sealed graft polymerization chamber, the monomer solution was applied to both sides, and immediately covered with a protective film (40 μm thick, low-density polyethylene film), the monomer solution was applied to the hydrophobic surface. The body aqueous solution was maintained uniformly.

As a monomer solution, a 30% aqueous solution of acrylamide was added with sodium methacrylate sulfite (Naps, o
, )/ferrous sulfate (IPeBO4.7H10) 1.3 mmol/9.0x10-' per 1002 aqueous solution
The one with millimole added was used. The reaction completes in 1 minute after passing through the graft polymerization chamber, and after peeling off the protective film,
A surface-treated film was obtained by washing with water in a washing tank.

The water wettability of this film is good, and the contact angle with respect to water is 35 degrees. It is clear that surface graft polymerization is possible even by continuous treatment for a short period of time.

Example 6 In Example 1, a 20% aqueous solution of sodium p-styrene sulfonate was used as the monomer solution, and the reducing agent sodium metaacid sulfite (Na, R205)/ferrous sulfate (Feso, -7H,O ) was added to 100 flC of the aqueous solution at a rate of 5.3 mmol/cm θxlO-j mmol. The obtained surface-treated film has good water wettability and has a contact angle of 20
It was degree.

Example 4 In Example 1, an ethylene-vinyl acetate copolymer film (containing vinyl acetate!15) was used as the raw polymer material film.
%, width 25 cm, length 100 μm) was used without pretreatment. The obtained surface-treated film had good water wettability, and the contact angle with water was 20 degrees. The contact angle of the untreated film with water was 75 degrees.

Example 5 In Example 1, a vinyl chloride resin film (hard, width 25 cm, thickness 60 μm) was used as the raw polymer material film.
Everything was carried out according to Example 1, except that the sample was used without pretreatment. The obtained surface-treated film had good water wettability, and the contact angle with respect to water was 32 degrees. The contact angle of the untreated film with water was 73 degrees.

[Brief explanation of drawings]

1 and 2 show one embodiment of the process for carrying out the surface treatment of polymeric materials according to the method of the invention. 1: Corona discharge, electrode 2: Corona discharge treatment roll 5 Niger raft polymerization chamber 4: Monomer supply port 5: Protective film 6: Washing tank 7: Drying chamber 8: Product winder 9: Net protective material 10: For reaction Winder patent applicant: Toyo Soda Kogyo Co., Ltd. Procedural amendment September 5, 1980 Mr. Kazuo Wakasugi, Commissioner of the Japan Patent Office 1. Indication of f'l: 1988 Patent Application No. 121] No. 184 2. Title of the invention Continuous Modification Method for the Surface of Molecular Materials 6 Relationship with the case of the person making the amendment Patent applicant telephone number (585) 3311 q, , -, , / 6 Column 7 for detailed description of the invention in the specification subject to the amendment Contents of amendment (1) “Thickness 10 μm” stated on page 13, line 14 of the specification
is corrected to "thickness 100 μm".

Claims (1)

[Claims] 1. 1 mJ/C211” to 10 JJ/C1 is applied to a flat polymeric material by corona discharge in the atmosphere.
After applying energy of After that, the protective material is peeled off, washed, and dried, and these steps are carried out continuously or semi-continuously while moving the polymeric material.