JPH062830B2 - Highly adhesive composite polyester molding - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a composite polyester molded product having good adhesiveness, and more particularly to a technique for changing the atomic composition of the surface of the molded product by corona discharge treatment while transferring the molded product. By appropriately adjusting the amount of change, it is intended to obtain a polyester molded product having excellent adhesiveness.

Surface modification of a plastic molded product by corona discharge is generally known as a surface treatment technique for a plastic film, and substantial effects such as improvement of adhesiveness due to surface activation have been obtained. But the result is not entirely satisfactory.

The present inventors sometimes pay attention to a polyester molded product, and when, for example, surface modification (especially improvement of adhesiveness) of a polyester film by corona discharge treatment, sufficient treatment efficiency is obtained at an actual production level. I thought of establishing a method that would allow me to do so.

As a corona discharge treatment method for plastic molded products, there is a technique for promoting a chemical change on the discharge surface by supplying an organic solvent to the discharge part, as seen in, for example, Japanese Patent Publication No. Sho 48-17747. It is difficult to apply it to a molded product that is expected to have such uses. Also Journal
of Applied Polymer Science, Vol.15, P.1365 ~ 1375 (19
71) describes a technique of performing corona discharge treatment in an inert gas atmosphere, and it is suggested that the effect of activation or deterioration depending on the difference in the treatment atmosphere. Therefore, based on this, a technique has been proposed in which the atmosphere is replaced with, for example, a low oxygen atmosphere to perform the treatment. However, various drawbacks are pointed out in the embodiment techniques proposed so far, as described below.

For example, in the method disclosed in Japanese Patent Laid-Open No. 55-50034, a reel for rewinding a plastic film, a reel for rewinding a plastic film, and a chamber for covering the entire film running space including a corona discharge treatment device provided therebetween are provided. It is to control the entire atmosphere of the chamber by viewing it as one closed space. Therefore, there is a problem in that a large amount of inert gas is required and a special shield mechanism for making the chamber itself a closed structure is required, the circumference of the device becomes complicated, and the cost increases due to these factors. Therefore, as a practical problem, a sufficient inert atmosphere is not guaranteed and the gas composition on the outermost surface of the film cannot be freely controlled.

Further, in JP-A-57-23634, a hood (hereinafter referred to as a first hood) for covering a corona discharge atmosphere is provided to perform local atmosphere control, and another hood (hereinafter referred to as a first hood) is provided in front of the first hood. 2 hood), and a control method is disclosed in which the main point is to blow an inert gas to the running film in the second hood. However, in this technique, for example, in the second embodiment, “from a slit directly below the pipe toward the film inlet side at a position of 45 ° to a slit C
Supplying O ₂ into the hood (Note: second hood) ”is recommended. From this description, the inert gas is intended only to be supplied into the second hood, and the gas blown out from the slit hits the inner wall surface of the second hood and diffusely fills the second hood. It is obvious that the film covers the surface of the film, and in the same publication, it is better that the discharge of the inert gas does not directly hit the discharge electrode, and the gas atmosphere in the first hood is It is described that the supply of the inert gas may be stopped once it is replaced with the inert gas, and the second hood is merely expected to have an auxiliary role of the first hood. It is clear that Therefore, it is a more practical method than the technique of replacing the previous atmosphere in the chamber with an inert gas, but it is still considered from the viewpoint of controlling the entire atmosphere in the hood until it gets tired. There is no idea to study by applying a spot to the outermost surface of the molded product, which is the most important for the product.

Incidentally, Japanese Patent Laid-Open No. 56-49737 has started a technique of blowing dry gas into the hood in order to prevent outside air from entering the corona discharge atmosphere. However, this technique only intends to replace the gas by sucking out and removing the wet gas in the hood and introducing the dry gas, and there is no idea that the outermost surface of the molded product is spotted. .

The reason why the conventional improvement processing method cannot achieve sufficient results can be considered as follows. That is, the result of corona discharge appears on the outermost surface of the molded product, and therefore, although the gas molding on the outermost surface of the molded product is important, the conventional improvement method simply means that the entire inside of the processing system or the chamber is treated. We only recognize that the control of the gas atmosphere is sufficient, and obstacles due to the accompanying flow (outside air) of the surface layer of the molded product that is carried in and run, that is, the overall gas atmosphere in the chamber and the outermost surface of the molded product. It seems that the difference in the gas composition covering the is not taken into consideration.

If the processing is performed in a batch-type stationary state, the obstacles described above will not be a problem, but since it will significantly reduce industrial productivity and raise the market price, it will eventually be used only for limited applications. Cannot be transformed. On the other hand, in order to obtain the desired treatment effect in the continuous production method as described above, the treatment speed must be considerably low, but this causes damage to the surface of the article to be processed of the molded article, resulting in poor appearance, Problems such as poor adhesion and maximum blocking will occur. In the conventional corona discharge treatment in the air atmosphere, the surface of the molded product is oxidized and an oxidative deterioration layer is formed on the surface.Therefore, even if the degree of corona discharge treatment is increased, the adhesiveness is kept above a certain level. It cannot be improved.

The present inventors have been more concerned about such circumstances and have conducted various studies. As a result, when nitrogen gas or a nitrogen-containing composite composition gas containing mainly nitrogen gas and having an oxygen content of 20% by volume or less was continuously sprayed from the bottom surface of the discharge side electrode to the treated surface of the object to be treated, The present inventors have completed the present invention, knowing that the amount of oxygen gas on the surface of a molded product becomes extremely small and that the treatment effect directly affected by nitrogen gas can be obtained. The reason why the corona discharge surface is mainly influenced by the nitrogen gas when the nitrogen gas or the nitrogen-containing composite composition gas having the oxygen content of 20% by volume or less is sprayed can be sufficiently clarified. Not, but you can think of it as follows. That is, the surface of the molded product transferred to the corona discharge part is accompanied by a considerable amount of air although it depends on the surface characteristics and the transfer speed, and its composition is generally oxygen: 21% by weight, nitrogen: 78%.
The capacity is%. On the other hand, the composition of the associated air on the surface of the molded product is not easily changed by the usual means as described above, for example, by adjusting the atmosphere in the chamber, but when the blowing means according to the present invention is adopted, the blowing gas is the entrained air. Since a part or all of the layer is discharged and replaced, the composition of the associated air layer changes. This change is due to the fact that the air containing 21% by volume of oxygen is replaced by the blowing gas containing 20% by volume or less of oxygen, so that the oxygen concentration decreases relatively,
On the contrary, the influence of nitrogen gas existing as the main component is increased, so that the effect which cannot be obtained by the conventional corona discharge treatment in the atmospheric atmosphere is exhibited. As described above, there is a point in that nitrogen gas or a nitrogen-containing composite composition gas having an oxygen content of 20% by volume or less is continuously sprayed from the bottom surface of the discharge side electrode to the treated surface of the molded article. Therefore, the gas component other than oxygen and nitrogen may be argon gas, helium gas, carbon dioxide gas, or the like, and in any case, the influence of nitrogen gas will be largely exerted.

Based on the improved results of the corona discharge treatment technology as described above, we attempted to apply it to a polyester molded product, and did not cause any inconvenience in terms of blocking property, slippage, etc., and the adhesiveness was remarkably improved. It was confirmed that the adhesiveness did not decrease even under high temperature and high humidity, and the present invention was completed.

That is, the gist of the present invention lies in the following points.

A molded product molded from a mixture of a polyester (A) composed of a dibasic acid residue of which 80 mol% or more is terephthalic acid and a glycol residue, and a block copolymerized polyester (B) is at least Corona discharge treatment is carried out by continuously transferring a pair of electrodes to a corona discharge treatment device, and nitrogen gas, or nitrogen containing mainly nitrogen gas and having an oxygen content of 20% by volume or less is contained. A composite composition gas is sprayed onto the corona discharge treated surface of the molded product, and at the time of spraying, the gas is discharged along the discharge generation direction from the surface of the discharge side electrode facing the molded product. By continuously spraying at a spraying speed of 10% or more of the transporting speed of the, the associated air layer carried into the corona discharge treatment device along with the transporting surface of the molded product is formed. With corrupted dispersed replacing the blowing gas, the respective change amounts of oxygen index and nitrogen index at the thin layer portion within 100Å from the outermost surface of the molded product surface changes from pre-corona discharge treatment to after the corona discharge treatment Δ
When the oxygen index and the Δnitrogen index are both ratios, the ratio [Δoxygen index / Δnitrogen index] is 0.2 to −3.5, and the nitrogen index after corona discharge treatment in the thin layer portion is 3 or more. Is a method for producing a highly adhesive composite polyester molded article.

(However, the oxygen index and the nitrogen index are determined by the following method. That is, using an ESCA spectrometer ES-200 type (manufactured by Kokusai Electric Co., Ltd.), 1 of carbon on the surface of the molded product is used.
The ratio of the integrated intensity obtained from the s orbital spectrum to the integrated intensity obtained from the peak corresponding to the binding energy of organic nitrogen from the 1s orbital spectrum of oxygen is calculated, and the ratio of the integrated intensity per 100 carbon atoms is calculated based on the integrated ratio. The oxygen number is calculated and this value is defined as the oxygen index. Further, regarding the nitrogen index, the number of nitrogens per 100 carbon atoms is determined by the same method, and this is defined as the nitrogen index. ) One of the polyester components (A) of the composite polyester of the present invention is composed of a dibasic acid (provided that 80 mol% or more of the dibasic acid is terephthalic acid) residue and a glycol residue. It is made of polyester. This dibasic acid residue is mainly a terephthalic acid residue.
Other dibasic acid residues of 0 mol% or less include residues of isophthalic acid, phthalic acid, adipic acid, sebacic acid, succinic acid, oxalic acid, etc., and residual oxyacids such as p-hydroxybenzoic acid. Groups can also be used. The glycol residue is an ordinary alkylene glycol residue, and examples thereof include ethylene glycol, propylene glycol, trimethylene glycol, tetramethylene glycol, hexamethylene glycol, and cyclohexanedimethanol. Particularly practically, the residues of ethylene glycol, tetramethylene glycol and cyclohexanedimethanol are used. A particularly solid polymer is polyethylene terephthalate or polytetramethylene terephthalate.

On the other hand, the other block copolymerized polyester (B)
Is a copolymer composed of a high-melting point crystalline polyester segment (C) and a low-melting point soft polymer segment (D) having a molecular weight of 400 to 10,000, and forms a high polymer only with the high-melting point crystalline polyester segment constituent components. In this case, the polymer has a melting point of 170 ° C. or higher, and has a melting point or softening point of 100 ° C. or lower when measured only with the low melting point soft polymer segment constituent components.

The high melting point crystalline polyester segment constituent component in the block copolymerized polyester has a melting point of 170 ° C. or higher when it is made into a high polymer showing fiber forming ability only by the constituent component. For example, terephthalic acid, isophthalic acid Acid, residues of aromatic dicarboxylic acids such as 1,5-naphthalenedicarboxylic acid and 2,6-naphthalenedicarboxylic acid, and ethylene glycol, propylene glycol, tetramethylene glycol, pentamethylene glycol, 2,2-dimethyltrimethylene glycol , Hexamethylene glycol, p-
Polyester consisting of residues of aliphatic, aromatic or alicyclic diol such as xylylene glycol and cyclohexanedimethanol, or oxyacid such as p- (β-hydroxyethoxy) benzoic acid and p-oxybenzoic acid In addition to the copolymerized polyester containing the above residue as a copolymerization component on the polyester, aromatic ethers such as 1,2-bis (4,4-dicarboxymethylphenoxy) ethane and di (4-carboxyphenoxy) ethane Aromatic amides such as polyetheresters and bis (N-paracarboethoxyphenyl) terephthalimide composed of dicarboxylic acid residues and diol residues similar to the above, and diol residues similar to the above And a polyamide ester composed of a group.

On the other hand, as the low melting point soft polymer segment constituent component, a polyether such as polyethylene oxide glycol, polypropylene oxide glycol, polytetramethylene oxyside glycol, copolymer glycol of ethylene oxide and propylene oxide, copolymer glycol of ethylene oxide and tetrahydrofuran, etc. , Polyneopentyl azelate, polyneopentyl adipate, aliphatic polyesters such as polyneopentyl sebacate, polylatons such as poly-ε-caproclatone and polypivalolactone.

These block copolyesters can be produced by a usual condensation polymerization method.

Specific examples of the block copolymerized polyester used in the present invention include polyethylene terephthalate-polyethylene oxide block copolymer, polytetramethylene terephthalate-polyethylene oxide block copolymer, polycyclohexane terephthalate-polyethylene oxide block copolymer, polycyclohexane. Terephthalate-polytetramethylene terephthalate block copolymer, polyethylene terephthalate-polytetramethylene oxide block copolymer, polytetramethylene terephthalate-polytetramethylene oxide block copolymer, polytetramethylene terephthalate-
Polytetramethylene oxide block copolymer, polyethylene terephthalate-polyethylene oxide-polypropylene oxide block copolymer, polyethylene terephthalate-poly-ε-caprolactone block copolymer, polytetramethylene terephthalate-poly-
ε-caprolactone block copolymer, polyethylene terephthalate-polypivalolactone block copolymer,
Polyethylene terephthalate-polyethylene adipate block copolymer, polyethylene terephthalate-polyneopentyl sebacate block copolymer, polytetramethylene terephthalate-polyethylene dodecaneate block copolymer, polytetramethylene terephthalate-
Polyneopentyl dodecanoate block copolymer, polyester block copolymer of di (4-carboxyphenoxy) ethane and ethylene glycol and polyethylene glycol, bis (N-paracarboethoxyphenyl) adipamide and ethylene glycol Examples thereof include block copolymers of polyethylene and polyethylene glycol.

The low melting point soft polymer segment (D), which is a constituent of the block copolyester (B), is contained in an amount of 0.3 to 20% by weight in the total mixed polymer (base polymer as a raw material for molding).
It is recommended to be present.

When the content of the low melting point segment (D) is less than 0.3% by weight, the total mixed polymer is composed of the polyester (A) and the high melting point crystalline polyester segment (C), and both (A) and ( C) is essentially the same,
The advantage of mixing the block copolymerized polyester (B) with the polyester (A), that is, the drawback of the polyester homomolded product (for example, in the case of a film, a bent portion is easily subjected to stress concentration and pinholes are generated, during high temperature treatment It is difficult to obtain the benefit of improving defects such as becoming brittle due to shrinkage or deterioration. However, if the content of the low melting point segment (D) exceeds 20% by weight, it is not preferable until the dissatisfaction in strength appears because the segment is generally amorphous. From the viewpoint of the blending ratio of the polyester (A) and the block copolymerized polyester (B), the transparency decreases as the blending ratio of the latter (B) increases. It is preferable to set the content to be not more than weight%. In the case of other molded products which are not required to have transparency, the amount may be further increased, but from the viewpoint of economy, it is preferable to set the upper limit to 60% by weight.

When the polyester (A) and the block copolymerized polyester (B) are mixed to obtain a raw material composition for molding, the block copolymerized polyester (B) is added to and mixed with the polyester (A). At the end of the polymerization of the block copolymer polyester (B)
There is a method of adding the block copolymerized polyester (B) immediately before the molding of the polyester (A), a method of adding the polyester chip and the block copolymerized polyester chip with a blender, and the like. Is also possible.

As the molded product of the present invention, a film or sheet (hereinafter simply referred to as a film) is exemplified as the most typical one, and is applied to a non-stretched film, a uniaxially stretched film, a biaxially stretched film, etc. Examples of the product include long products such as fibers, pipes, tapes, woven fabrics, and non-woven fabrics.

When the molded product is formed by using the composite polyester raw material, it may be produced only from the composite polyester raw material, but it may be blended with another polymer component in a range that does not adversely affect the properties of the polyester molded product. Well, generally, the amount is 20% by weight or less based on the total weight of the composition. The polymer component that may be blended may be determined in consideration of the type and properties of the molded product.

In addition to polymer components, stabilizers, lubricants, anti-blocking agents, anti-fog agents, UV absorbers, flame retardants, clarifiers, antioxidants, light stabilizers, antistatic agents, in consideration of the type and use of molded articles. , Additives such as dyes and pigments may be contained,
Those that do not adversely affect the implementation of corona discharge, whether alone or in combination, are included in the scope of the present invention.

In producing a polyester molded article using a polyester composition comprising the above-mentioned materials, it is sufficient to follow a known method for each molded article, and the scope of the present invention depends on the peculiarity of the production means. It does not depart from. Therefore, the manufacturing method of the molded product may be freely selected, but since the typical molded product to which the present invention is applied is a film, the manufacturing method of the film will be described as follows.
That is, an unstretched film is first formed by forming the composition raw material by a normal polyester film forming method, for example, a T-die method or an inflation method. If this is stretched uniaxially or biaxially, a film having satisfactory strength can be obtained. The corona discharge treatment described below may be carried out as one of all film forming steps after the stretching step, and in some cases, the product once wound may be rewound to perform corona discharge. May be adopted.

In the present invention, the polyester molded product is treated, and the molded product is continuously transferred to a corona discharge treatment device having at least one pair of electrodes facing each other for surface treatment. Nitrogen gas or a gas having a nitrogen-containing composite composition containing nitrogen gas as a main component and having an oxygen content of 20% by volume or less [specifically, one in which a part of oxygen is removed from the applied amount, or other than oxygen in the air] a material obtained by adding an appropriate amount, even N ₂ alone or its _{H 2, Ar, CO 2,} X
_{e, Kr, Cl 2, NH} 3, ( abbreviated below for convenience inert gas) NO _X as a mixture of inert gas and the ionizable gas such as, etc.]
Is continuously sprayed onto the treated surface from the bottom surface of the discharge side electrode.
At the time of the spraying, the gas is sprayed along the discharge generation direction from the surface of the discharge side facing the molded product. That is, the blowing direction is an important point of the present invention, and the blowing gas is blown from almost directly above the molded product, whereby the associated air layer can be destroyed and dispersed.

Further, the spraying speed needs to be 10% or more of the transfer speed of the polyester molded product. Then, as will be described later in detail, the relationship between the oxygen index and nitrogen index before and after corona discharge treatment in the thin layer portion (the portion that has an important influence on the adhesiveness) within 100 Å from the outermost surface of the treated surface is strictly specified. Polyester with excellent adhesion to various materials (for example, metals; various inks, especially cellulosic inks and water-based inks; resins such as vinylidene chloride homopolymers or copolymers and functional group-containing resins) A molded product can be obtained.

Although the following will clarify the configuration and the effect of the present invention in conformity with the drawings of the examples, the structure and arrangement of the discharge-side electrode shown in the drawings, and the shape of the cover are merely representative examples.
Further, since the drawings only show examples of application to a plastic film, it is within the technical scope of the present invention to change the design under the condition that it does not violate the spirit of these descriptions.

FIG. 1 is a sectional view showing an essential part of an embodiment of the present invention, and FIG. 2 is a perspective view showing a part of a discharge side electrode. In the figure, 1 is a metal drum, 2 is an electrode cover, and 3 is a discharge. A side electrode, 4 is a gas supply pipe, 5 is a gas ejection port, and 6 is a running film. That is, the film 6 is introduced from the direction of the arrow B to the metal drum 1 rotating in the direction of the arrow A, and further travels in the direction of the arrow C, but with the discharge side electrode 3 connected to a high voltage generator (not shown). Hundreds of KC between metal drum 1 covered with polyester, epoxy resin, ceramics, chlorphonated polyethylene, EP rubber, silicone rubber, etc.
/ S high frequency corona generated by applying a high voltage of several thousand to tens of thousands of V, for example, in the natural atmosphere, ozone or nitric oxide is generated to form a carbonyl group on the surface of the film 6. The surface is polarized by forming a carboxyl group and a carboxyl group. On the other hand, if it is a conventional example,
Oxygen in the atmosphere produces an oxidative deterioration product that inhibits the adhesiveness on the film surface. However, in the case of this example, the entire corona discharge atmosphere is shielded from the atmosphere by the electrode cover 2, and the gas ejection port 5 is provided on the bottom surface of the discharge side electrode 3 to face the surface of the film 6 so that the discharge side electrode 3 is covered. Since the inert gas is blown almost vertically from the bottom surface, the accompanying air layer covering the surface of the molded product is destroyed and a low oxygen atmosphere (controlled by the composition of the blown gas) The surface of the molded article will be covered by (inside the electrode cover 2), and the oxygen content in the coating gas will be substantially reduced, whereby the effect of nitrogen gas will appear significantly and the surface layer of the film 6 will be affected. The corona discharge effect is maximized.

This situation will be described in more detail below. That is, the film 6 entering at a considerably high speed in the direction of arrow B.
On the surface of, a slight air layer is formed,
By simply replacing the entire atmosphere of the corona discharge portion with an inert gas according to the conventional method, the outermost surface of the film 6 is still in the atmospheric atmosphere. Therefore, in carrying out the present invention, an inert gas is strongly blown onto the film surface from the direction as shown in FIG. 3, and the associated air layer 7 is destroyed and dispersed by the jet air flow 8. The gas resuscitation in the associated air layer 7 on the film surface is modified to increase the proportion of nitrogen gas. In some cases, the surface can be replaced almost completely with an inert gas.

The flow velocity of the jet air flow 8 required to destroy and disperse the associated air layer 7 and obtain the above-mentioned effect cannot be uniformly determined because it depends on the shape and size of the molded product, the speed of loading into the corona discharge treatment device, and the like. As a result of the experiment, it has been found that it is most preferable to determine it based on the entry speed of the associated air layer 7 (in other words, the loading speed of the molded product). Generally, it is convenient to understand that the gas blowing speed is expressed in seconds and the film transfer speed is expressed in minutes.
In the present invention, it is decided to follow such a convention. That is, it is desirable that the value of the blowing gas velocity when expressed in seconds is 10% or more of the value of the transfer speed of the molded product when expressed in minutes, and it is preferably 40%. By doing the above, the associated air layer 7 can be destroyed and dispersed to the extent that there is substantially no inconvenience. The spray angle of the jetted gas to the film can be freely selected by obtaining the effective angle. Generally, the speed of loading the molded product is 1 to 500.
It is about m / min.

By adopting such conditions, the associated air layer can be destroyed and dispersed, and at the same time, the vicinity of the corona discharge part can be protected by an inert gas atmosphere. In addition, the electrode cover 2 has a primary function of protecting the electrode 3 from a mechanical impact rather than a function of maintaining an atmosphere, and a secondary function of suppressing the accompanying flow. Therefore, in carrying out the present invention, the electrode cover 2 may be removed from time to time, but in order to suppress the consumption of the inert gas, it is desirable to review the function for maintaining the atmosphere again. As shown in FIG. 4, if the lower end (film side) of the cover 2 is squeezed and the inert gas is introduced into the cover 2 from the conduit 10, the gas is converged along the inner surface of the slope 9. Flow in the direction of the arrow, and the gas curtain effect is exhibited at the inlet of the cover 2. That is, the invasion of the associated air layer is blocked on the inlet side, and the existence value of the electrode cover 2 is further improved.

Further, as shown in FIG. 5, the extension cover 11 is provided especially at the entrance.
By providing this and making it close to the surface of the molded product, the inert gas leaking from the inside of the cover 2 will be filled in the extension cover 11, so that the associated air layer entering from the cover 11 As it advances in the cover 11, it is gradually broken and dispersed. Therefore, when reaching the corona discharge atmosphere portion, the degree of substitution with the inert gas becomes extremely high, and the effect of the present invention is more remarkably exhibited. When the apparatus shown in FIG. 5 is used, the inert gas can be sprayed from the extension cover 11, and the spray angle in this case can be freely selected. As a result, the destruction and dispersion efficiency for the associated air layer is extremely high.

On the other hand, on the exit side of the film 6 (on the right side in FIG. 4), the gas in the cover 2 is discharged along with the running film. Although it is not necessary, in the sense of reducing the consumption of inert gas as described above, it is meaningful to pay the same consideration as for the inlet side. In order to exert the above-mentioned sealing function on the inlet side and the outlet side of the cover 2 to the minimum, the film should be discharged to the film surface at a speed of at least 10% or more, preferably 40% or more, with respect to the running speed of the film. Is desired. Regarding the ejection speed of the inert gas, only the lower limit side was described for both the gas ejection port 5 and the inlet / outlet port of the cover 2, but there is no need to set a practical upper limit, and economic efficiency and the required quality of the final product are required. It may be decided appropriately depending on the balance with

By setting the above treatment conditions, the treatment effect of corona discharge is enhanced and the adhesiveness is greatly improved.
In order to exert such effects constantly and stably, it was necessary to quantitatively understand the surface characteristics of the molded product before and after the treatment, and further research was conducted. as a result,
(1) Ratio of the amount of change in oxygen index and nitrogen index before and after corona discharge treatment in the thin layer area within 100Å of the surface of the molded product [Δ oxygen index / Δ nitrogen index], and (2) Within 100Å of the film surface It was found that a high degree of adhesion can be guaranteed by strictly controlling the nitrogen index after the corona discharge treatment in the thin layer portion of. That is, the above-mentioned fact is that [Δ oxygen index / Δ nitrogen index] is 0.2 to -3.5 in the above (1), and the nitrogen index after treatment is 3 or more in the above (2). In addition, by strictly controlling the treatment conditions and atmosphere of corona discharge, for example, metals, various printing inks (especially cellulose-based inks and water-based inks), vinylidene chloride-based homopolymerization or copolymerization resins, functional group-containing resins, etc. It is possible to dramatically improve the adhesiveness with various synthetic resins and the like, which will be described in more detail below.

First, a polyester molded product satisfying the requirement of [nitrogen index ≧ 3] defined in the present invention can be obtained occasionally even under the conventional treatment conditions, and can also be realized by a corona discharge treatment under a known nitrogen gas atmosphere. is there. However, as explained above, it is difficult to put it to practical use on an industrial scale, because a large-scale facility is required to secure the above-mentioned high-level nitrogen index in the conventional method for at least continuous treatment. It was On the other hand, if the method of the present invention is adopted, the nitrogen index can be easily increased to 3 or more with relatively simple equipment. On the other hand, the adhesiveness of various plastic materials
There is also a report that it is simply determined by the nitrogen index obtained by the ESCA method. However, such a report captures only one aspect of the influence on the adhesiveness. By the way, if the N-containing component is blended with the material, the nitrogen index will increase, but taking into account the fact that only by mixing the N-containing component, an antistatic agent or a lubricant, the adhesiveness does not improve, but rather decreases. It is obvious that a mere increase in the nitrogen index does not immediately lead to an improvement in the adhesiveness.

Therefore, other factors that affect the adhesiveness were also examined. The value calculated by the above [Δ oxygen index / Δ nitrogen index] almost accurately represents the corona discharge treatment effect, that is, the adhesiveness improving effect. It was confirmed the fact that those treated with a value of 0.2 to -3.5 exhibit a high level of adhesion, which serves the purpose. By the way, even if the nitrogen index within 100 Å of the surface layer after the treatment shows 3 or more, if the [Δ oxygen index / Δ nitrogen index] exceeds 0.2, the corona discharge treatment effect is insufficient and a high level of adhesiveness is obtained. Can't get From this point of view, it is essential to adopt the treatment method of the present invention and control the treatment conditions such that the nitrogen index is 3 or more and the [Δ oxygen index / Δ nitrogen index] is 0.2 to −3.5. This ratio is -3.5
It was practically extremely difficult to make it smaller.

By the way, regarding [Δ oxygen index / Δ nitrogen index], the oxygen atoms constituting the polyester, the oxygen atoms in other polymers that can be blended, or the unique oxygen atoms in various additives are released and removed by the inert gas. Or, as a result of substitution and removal by nitrogen atoms in the inert gas, as a result, a negative value may result as described above. In this minus region, generally in the region of -1.0 to 0, the preferable result that the change of the adhesive force with time becomes extremely small and the blocking resistance is improved is obtained.

The present invention is configured as outlined above, so as to define the corona discharge treatment conditions, and to always grasp the treatment effect from the amount of change in the oxygen index and nitrogen index of the surface layer portion before and after the treatment, It has become possible to reliably obtain a polyester molded product having excellent adhesion to various materials. In particular, the effect of improving adhesiveness is exhibited even after long-term exposure under high temperature and high humidity, and the surface layer with improved adhesiveness does not easily peel off from the base layer portion. When the film is a film, the surface layer does not shift to the back side during winding and storage, and there is no concern that the printing ink will peel off when it is actually applied as a film package. Further, since the adhesiveness with other film base materials is also improved, the laminated film does not peel off after long-term storage.

Next, the effects of the present invention will be clarified by listing experiments. The evaluation method of the surface characteristics used in the experimental example is as follows.

(A) Haze Measured by JIS-K-6714 (B) Lamination strength After printing with cellophane ink, polyethyleneimine is coated, and after drying, low density polypropylene at 290 ° C is melt extruded to a thickness of 30 μm. Laminate. Immediately thereafter, or after storage or treatment under various conditions, the film and the polypropylene layer are peeled off and the adhesive strength thereof is measured. The peeling conditions are 180 degree peeling and speed 2
00 mm / min.

However, the boiling water-treated and retort-treated products were laminated with an isocyanate-based adhesive, and after laminating, they were aged at 40 ° C. for 2 days and then evaluated.

Film production example 83 parts of dimethyl terephthalate, 110 parts of 1,4-butanediol, 215 parts of poly (tetramethylene oxide) glycol (PTG) having a molecular weight of 2000, and 0.6 parts of an antioxidant (Ionox 330: Shell Chemical Co., Ltd.). Polytetramethylene terephthalate-polytetramethylene oxide block copolymer (terephthalate) obtained by adding 0.03 part of tetra-n-butyl titanate as a catalyst to an autoclave, heating with stirring, transesterification, and then polycondensation. With an acid to PTG molar ratio of 4: 1), an intrinsic viscosity of 0.
65 dl / g of polyethylene terephthalate, 6% by weight of the former,
The latter was added at a ratio of 94% by weight and mixed and melted. This was extruded on a film, and the obtained film was stretched 3.3 times in the longitudinal direction at 87 ° C. and then 3.3 times in the transverse direction at 95 ° C., and further heat-set at 220 ° C. for 5 seconds. The obtained film was a transparent film having a thickness of 12 μm.

Using the apparatus shown in FIG. 1, the film obtained above was subjected to corona discharge under the conditions shown in Examples (1) to (3) of the present invention and Comparative Examples (1) to (3) in Table 1. It was submitted to processing. This embodiment (1) to (3)
In this case, a gas in which nitrogen gas and air are mixed is supplied from the gas supply pipe 4 and corona discharge is performed while continuously spraying from the gas ejection port 5. Further, in the comparative example (1), nitrogen gas was supplied into the electrode cover 2 and the discharge atmosphere was the same as that of the embodiment.
Although the same (O ₂ = 0.1%) as in (1) and (2) was used, the case was not sprayed from the gas ejection port 5, and the comparative example
(2) is a case of performing corona discharge treatment in the general atmosphere, Comparative Example (3) when the corona discharge in the same manner as in Example (1) except that the spraying speed is 0.2 m / sec Is. The ESCA value is also shown in Table 1.

When the haze and laminate strength of the film subjected to corona discharge treatment were determined, the results shown in Table 2 were obtained.

As is clear from Tables 1 and 2, in Comparative Examples (1) to (3),
[Δ oxygen index / Δ nitrogen index] is high, and removal of air from the film surface is insufficient. On the other hand, Example (1)
In (3) to (3), the [Δ oxygen index / Δ nitrogen index] was in the range of 0.2 to −3.5, and it was found that the adhesiveness was excellent. That is, by adopting the constitution of the present invention, it is possible to remove the associated air layer on the film surface for the first time, and if the discharge atmosphere is simply a nitrogen atmosphere, or if the spraying is insufficient, the It was confirmed that the removal of air was not achieved.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing an implementation state of the present invention, FIG. 2 is a sketch diagram illustrating a discharge side electrode used in the present invention, FIG. 3 is an explanatory diagram showing a destruction state of an associated air layer, and FIGS. The figure is an explanatory view showing an example of the electrode cover. 1 ... Metal drum 2 ... Electrode cover 3 ... Discharge side electrode 5 ... Gas ejection port 6 ... Film

Claims (1)

[Claims] 1. A polyester (A) composed of a dibasic acid residue having a terephthalic acid content of 80 mol% or more and a glycol residue, and a block copolymerized polyester (B).
In carrying out corona discharge treatment by continuously transferring a molded product molded from a mixture of the above to a corona discharge treatment device having at least one pair of electrodes facing each other, nitrogen gas or nitrogen gas as a main component A nitrogen-containing composite composition gas having a content of 20% by volume or less is sprayed onto the corona discharge treated surface of the molded product, and at the time of spraying, the discharge generation direction is from the surface of the discharge side electrode facing the molded product. Along with 10% of the transfer rate of the molding
By continuously spraying at the above spraying speed, while destroying and dispersing the associated air layer that is carried into the corona discharge treatment device along with the transfer surface of the molded product and is replaced with the spraying gas, 100 from the outermost surface of the molding surface
When the oxygen index and the nitrogen index in the thin layer within Å change from before corona discharge treatment to after corona discharge treatment, Δoxygen index and Δnitrogen index are taken as the ratio of both [Δ
[Oxygen index / Δnitrogen index] is 0.2 to −3.5, and the nitrogen index after corona discharge treatment in the thin layer portion is 3 or more. (Here, the oxygen index and the nitrogen index are determined by the following method: That is, the integrated intensity obtained from the 1s orbital spectrum of carbon on the surface of the molded article using an ESCA spectrometer ES-200 type (manufactured by Kokusai Electric Co., Ltd.), The ratio with the integrated intensity obtained from the peak corresponding to the binding energy of organic nitrogen was calculated from the 1s orbital spectrum of oxygen, and the number of oxygen per 100 carbon atoms was calculated based on the integrated ratio. Also, regarding the nitrogen index, the number of nitrogen per 100 carbon atoms is determined by the same method, and this is defined as the nitrogen index.)