JPWO2007097250A1 - Marking ink - Google Patents

Abstract

Marking ink that can mark the outer surface of the article by dyeing without forming a film of the film-forming resin on the outer surface of the article made of polyvinyl chloride resin, and has excellent discrimination after the marking. I will provide a. For each of the organic solvent and oil-soluble dye contained in the marking ink and the polyvinyl chloride resin forming the article marked by the marking ink, the absolute value of the difference in solubility parameter between them is respectively It needs to be below a certain value.

Description

  The present invention relates to a marking ink for marking an outer surface of an article made of a polyvinyl chloride resin.

  Conventionally, in this kind of marking ink, an ink containing a colorant, a film-forming resin, and an organic solvent is employed. This ink is used for marking by coloring a resin film on the outer surface of an article made of a polyvinyl chloride resin.

  Here, since the film-forming resin which is one of the components of the ink described above is difficult to adhere to the polyvinyl chloride resin, the improvement in the adhesion between the film forming resin and the polyvinyl chloride resin is considered. Various proposals have been made.

For example, it is disclosed that the non-aqueous inkjet ink for a polyvinyl chloride resin sheet described in Patent Document 1 should contain a specific organic solvent that dissolves the polyvinyl chloride resin as an essential component. .
JP 2005-15672 A

  However, the ink-jet ink described in Patent Document 1 is only intended to improve the adhesiveness with a polyvinyl chloride resin by a film-forming resin, just like the conventional marking ink.

  Therefore, the problem that the above-mentioned resin film peels from the outer surface of the article made of polyvinyl chloride resin cannot be solved.

  Therefore, in order to deal with the above-described problems, the present invention marks the outer surface of the article by dyeing without forming a film of the film-forming resin on the outer surface of the article made of polyvinyl chloride resin. In addition, an object of the present invention is to provide a marking ink having excellent discrimination after marking.

  In solving the above problems, the present inventors, as a result of diligent research, used organic solvent and oil-soluble dye contained in the marking ink, and the marking ink without using a film-forming resin in the marking ink. It has been found that the above-mentioned object can be achieved when the constituents of the polyvinyl chloride resin forming the article to be marked have a certain relationship with each other in their properties.

That is, the marking ink according to the present invention contains an organic solvent and an oil-soluble dye in the marking ink for marking the outer surface of an article made of a polyvinyl chloride resin, and the organic solvent is dissolved. When the solubility parameter is δ1, the solubility parameter of the oil-soluble dye is δ2, and the solubility parameter of the polyvinyl chloride resin is δ3, the following formulas | δ1-δ2 | ≦ 2.0 (J / cm ³ ) ^1/2 ---------- (1)
| Δ1-δ3 | ≦ 2.0 (J / cm ³ ) ^1/2 ---------- (2)
| Δ2-δ3 | ≦ 2.0 (J / cm ³ ) ^1/2 ---------- (3)
Is established.

  Here, the solubility parameter is a value used when evaluating the ease of dissolution of the non-electrolyte in the organic solvent. That is, those having similar solubility parameter values are well-melted or have an affinity. The solubility parameters were originally proposed by Hildebrand and Scott, then developed by Hansen and are widely used today.

Here, each of the above relational expressions will be described. First, in the formula (1), the absolute value of the difference between the solubility parameter (δ1) of the organic solvent and the solubility parameter (δ2) of the oil-soluble dye is 2.0 (J / cm ³ ) ^1/2. It is necessary to be within the following range. Thereby, the affinity between the organic solvent and the oil-soluble dye is increased, and the oil-soluble dye is well dissolved in the organic solvent.

In the formula (2), the absolute value of the difference between the solubility parameter (δ1) of the organic solvent and the solubility parameter (δ3) of the polyvinyl chloride resin is 2.0 (J / cm ³ ) ^1. Must be within the range of ^{/ 2} . Further, it is preferably within 1.0 (J / cm ³ ) ^1/2 or less. Thereby, when the marking ink comes into contact with the outer surface of the article made of the polyvinyl chloride resin, the outer surface instantly swells and is easily dyed with the dye.

Next, in equation (3), the absolute value of the difference between the solubility parameter (δ2) of the oil-soluble dye and the solubility parameter (δ3) of the polyvinyl chloride resin is 2.0 (J / cm ^3). ) It must be within the range of ^1/2 or less. Further, it is preferably within 1.0 (J / cm ³ ) ^1/2 or less. As a result, the affinity between the oil-soluble dye and the polyvinyl chloride resin is increased, and the polyvinyl chloride resin is stably dyed with the oil-soluble dye.

  By satisfying all of the above formulas (1), (2) and (3), in the marking ink according to the present invention, the film-forming resin is formed on the outer surface of the article made of the polyvinyl chloride resin. Without forming a film by the above, it is possible to provide a marking ink that can mark the outer surface of the article by dyeing and has excellent discrimination after the marking.

  Hereinafter, an embodiment of the marking ink according to the present invention will be described in detail. The marking ink referred to in the present embodiment is used when marking the outer surface of a covering member of a polyvinyl chloride resin-coated electric wire employed as a constituent member of a wire harness by an ink jet method.

  In the present invention, an article made of a polyvinyl chloride resin means an article having at least an outer surface formed of a polyvinyl chloride resin. In the present embodiment, the article refers to the polyvinyl chloride resin-coated electric wire produced by coating a bare electric wire with a polyvinyl chloride resin that is an electrically insulating resin.

  Here, the polyvinyl chloride resin refers to a general-purpose plastic obtained by polymerizing vinyl chloride monomers. In addition to those obtained by polymerizing vinyl chloride monomers alone, those obtained by copolymerizing with other monomers such as vinyl acetate and acrylate esters are also included. Is included.

  Polyvinyl chloride resins are generally processed into various products by methods such as extrusion molding and injection molding, but additives such as plasticizers and heat stabilizers may be mixed during molding. .

  In the present invention, the marking ink is used when marking the outer surface of an article made of polyvinyl chloride resin, and for the purpose of distinguishing between articles by a certain color and pattern, It refers to all inks used for bar code assignment, production number printing, or printing. In the present embodiment, the marking ink is used for marking by an inkjet method.

  Here, any of an on-demand format and a continuous format may be employed as an inkjet ejection format. In the case of adopting the continuous type, it is necessary to add a component that gives appropriate electrical conductivity to the ink. However, in this case, it must be added within a range that does not affect the present invention.

  In addition, as a discharge method, for example, any method such as a thermal ink jet method, a bubble jet (registered trademark) method, a piezo method, an electrostatic actuator method, or the like may be adopted.

  In the present embodiment, the drying of the marking ink after application by the inkjet method is not particularly limited. The drying temperature may be arbitrary, and may be natural drying at normal temperature, or forced drying with warm air, conduction or radiation at a predetermined temperature.

  In this embodiment, the marking ink is obtained by dissolving an oil-soluble dye in an organic solvent.

  Here, the organic solvent is not limited to the following, for example, alcohol solvents such as methyl alcohol, ethyl alcohol, isopropyl alcohol, butyl alcohol, and benzyl alcohol, and polyhydric alcohols such as ethylene glycol and glycerin. Solvents, ether solvents such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, dioxane, tetrahydrofuran, ester solvents such as ethyl acetate, ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, n-hexane, cyclohexane , Hydrocarbon solvents such as benzene, toluene and mineral spirits, and nitrile solvents such as acetonitrile. Of these, acetone and methyl ethyl ketone are particularly preferred in the present embodiment.

  The organic solvent in the marking ink can be used by appropriately mixing two or more organic solvents in relation to the oil-soluble dye to be employed and the polyvinyl chloride resin to be marked.

  In particular, when acetone or methyl ethyl ketone and another organic solvent are mixed and used, the mixed organic solvent preferably contains acetone or methyl ethyl ketone at 80% or more of its volume fraction.

  Next, the oil-soluble dye is not limited to, for example, CI Solvent Yellow 2, 13, 14, 16, 21, 25, 33, 56, 60, 88, 89, 93, 104, 105, 112, 113, 114, 157, 160, 163, CI Solvent Red 3, 18, 22, 23, 24, 27, 49, 52, 60, 111, 122, 125, 127, 130, 132, 135, 149 , 150, 168, 179, 207, 214, 225, 233, CI Solvent Blue 7, 14, 25, 35, 36, 59, 63, 67, 68, 70, 78, 87, 94, 95, 132, 136, 197, CI Solvent Black 3, 7, 28, 29, CI Solvent Violet 8, 13, 31, 33, 36, CI Solvent Orange 11, 55, 60, 63, 80, 99, 114, CI Solvent Brown 42, 43, 44, CI Solvent Green 3, 5, 20 etc. In addition, commercially available oil-soluble dyes to which C.I.No. is not given can also be used.

  In addition, the oil-soluble dye may include disperse dyes, pigments, vat dyes, basic dyes, and the like that can be used for this purpose. For example, CI Disperse Yellow 54, 82, 160, CI Disperse Red 22, 60, CI Disperse Blue 14, 197, CI Disperse Violet 13, 28, 31, 33, 57, CI Pigment Yellow 147, CI Pigment Red 181, CI Vat Red 41, CI Basic Blue 7, etc.

  Further, the oil-soluble dye in the marking ink can be used by appropriately blending depending on the desired marking hue. Moreover, the usage-amount of the said oil-soluble dye can be suitably determined with the density | concentration of marking.

As described above, in this embodiment, the marking ink for marking on the outer surface of the covering member of the polyvinyl chloride resin-coated electric wire using the inkjet method contains an organic solvent and an oil-soluble dye. When the solubility parameter of the organic solvent is δ1, the solubility parameter of the oil-soluble dye is δ2, and the solubility parameter of the polyvinyl chloride resin is δ3, the following formulas | δ1-δ2 | ≦ 2 .0 (J / cm ³ ) ^1/2
| Δ1-δ3 | ≦ 2.0 (J / cm ³ ) ^1/2
| Δ2-δ3 | ≦ 2.0 (J / cm ³ ) ^1/2
Is established.

  Here, a method for obtaining the solubility parameter of each of the organic solvent, the oil-soluble dye, and the polyvinyl chloride resin will be described. In the present invention, there are various methods for determining the solubility parameter.

  First, the value (δ1) of the solubility parameter of the organic solvent can be obtained from literature values. For example, the value (δ1) is as described in POLYMER HANDBOOK 4th Edition (J. Brandrup, E. H. Immergut, and E. A. Grulke, Editors).

  When two or more kinds of organic solvents are mixed and used, the solubility parameter value (δ1) of the mixed organic solvent is the solubility parameter of each organic solvent to be mixed and each volume fraction. Can be calculated based on the above. For example, the calculation method is based on Hideki Yamamoto, “SP Value Basics / Applications and Calculation Methods”, Information Organization (2005).

  Next, the value (δ2) of the solubility parameter of the oil-soluble dye is rarely published in literature values, and in this case, it is obtained by measurement. That is, the value (δ2) is obtained by conducting a dissolution experiment using various solvents with known solubility parameters, and obtaining a solubility parameter of the oil-soluble dye as a solute from the solubility parameter of the solvent having the highest solubility. .

  In this method, δd (dispersion force term), δp (polarity term), and δh (hydrogen bond term), which are each component (Hansen's parameter) of each solubility parameter of the solvent having the highest solubility, are set for each term. Plot the data to find the center value for each term. As the value of each term of the solubility parameter of the substance for which the solubility parameter is to be obtained, this central value can be used to obtain the solubility parameter of the unknown substance. For example, details of this method can be found in The Book and Paper Group ANNUAL Vol. 3 (1984) “Solubility Parameters: Theory and Application”.

  Further, the solubility parameter value (δ3) of the polyvinyl chloride resin is copolymerized as described above, has an individual molecular weight, and it is difficult to use a general value such as literature.

  Therefore, the value (δ3) is obtained by measurement. In this case, in the method of obtaining from the solubility by the above-described dissolution experiment, the obtained value may vary. In such a case, the value (δ3) is obtained by Turbididimetric Titration. That is, a resin for which a solubility parameter is to be obtained is dissolved in a good solvent having a known solubility parameter, and a titration experiment is performed using a poor solvent having a large solubility parameter and a poor solvent having a small value, respectively. Measure each cloud point. The value of the solubility parameter of the resin can be obtained by a calculation formula shown in the following literature. For example, the calculation formula is based on K. W. SUH, D. H. CLARKE, JOURNAL OF POLYMER SCIENCE: PART A-1, Vol. 5, 1671-1681 (1967).

  By the above method, the solubility parameter of each of the organic solvent, the oil-soluble dye, and the polyvinyl chloride resin can be obtained.

  Hereinafter, in the present embodiment, the following examples were prepared and evaluated. The present invention is not limited to these examples.

Marking ink adjustment:
Combination of two organic solvents (acetone and methyl ethyl ketone) and five oil-soluble dyes (CISolvent Blue 70, CISolvent Violet 33, CISolvent Yellow 56, CISolvent Red 233 and CISolvent Blue 68) After sufficiently stirring and dissolving in an organic solvent (acetone or methyl ethyl ketone), the mixture was filtered using a 1.0 μm membrane filter to obtain six types of marking inks, ink-1 to ink-6.

Marking test:
Using a piezo-type inkjet device (nozzle diameter: 0.1 mm), each of ink-1 to ink-6 was applied to the outer surface of the covering member of the polyvinyl chloride resin-coated electric wire (outer diameter: 1.3 mm). And dried with hot air at 40 ° C.

Solubility parameters:
In Ink-1 to Ink-6, the solubility parameter (δ1) of the organic solvent (acetone and methyl ethyl ketone) was determined from literature values. The solubility parameters (δ2) of the six types of oil-soluble dyes were determined by dissolution experiments. In addition, the solubility parameter (δ4) of the polyvinyl chloride resin was determined by turbidimetric titration from the coated member of the coated electric wire.

  From the above, for the ink-1 to ink-6 obtained in this example, the combination of the oil-soluble dye and the organic solvent used, the value of the solubility parameter of each component obtained, and the solubility parameter of each component The absolute value of the difference is shown in Table 1.

In Table 1, methyl ethyl ketone is indicated by “MEK” for the organic solvent, CISolvent Blue 70 is indicated by “Blue 70” for the oil-soluble dye, and the polyvinyl chloride resin is indicated by “PVC” for the resin forming the article. It showed in.

  According to Table 1, it can be seen that the marking inks according to Ink-1 to Ink-6 all satisfy the conditions according to the present invention.

Comparative example

Marking ink adjustment:
Combining two organic solvents (cyclohexane and cyclohexanone) and two oil-soluble dyes (CISolvent Yellow 88 and CISolvent Red 233), 3% by weight of each dye, and thoroughly stirring the organic solvent (cyclohexane and cyclohexanone) After dissolution, the mixture was filtered using a 1.0 μm membrane filter to obtain three types of marking inks, ink-7 to ink-9.

Marking test:
The same method as in the above example was used.

Solubility parameters:
In Ink-7 to Ink-9, the solubility parameter (δ1) of the organic solvent (cyclohexane and cyclohexanone) was determined from literature values. The solubility parameter (δ2) of the two types of oil-soluble dyes was determined by dissolution experiments in the same manner as in the above examples. Further, the solubility parameter (δ4) of the polyvinyl chloride resin was determined by nephelometric titration from the coated member of the coated electric wire as in the above example.

  From the above, for the ink-7 to ink-9 obtained in this comparative example, the combination of the oil-soluble dye and the organic solvent used, the value of the solubility parameter of each component obtained, and the solubility parameter of each component The absolute value of the difference is shown in Table 2.

  In Table 2, for example, C.I. Solvent Yellow 88 is indicated by “Yellow 88” for the oil-soluble dye, and the polyvinyl chloride resin is indicated by “PVC” for the resin forming the article.

  According to Table 2, it can be seen that the marking inks according to Ink-7 to Ink-9 do not satisfy one or more of the three conditions according to the present invention.

  Next, the discriminability of the coated electric wires after marking was evaluated for the inks 1 to 9 of the examples and the comparative examples. Marking clarity and dyeability were adopted as evaluation items. Moreover, the said dyeability was evaluated by the cellophane tape method and the friction transfer method.

  The evaluation of the clarity of the marking was visually evaluated for the covered electric wire after marking by inkjet. The evaluation was performed in three stages: ○: marks can be distinguished well, Δ: marks are difficult to distinguish, and X: marks cannot be distinguished.

  As an evaluation of the dyeability, the cellophane tape method is a state where cellophane tape (cellophane adhesive tape manufactured by Nichiban Co., Ltd.) is applied to the marking surface of the covered electric wire, and then the cellophane tape is peeled off and transferred to the cellophane tape. And the possibility of distinguishing marks after peeling. The evaluation was made in three stages: ○: the cellophane tape did not move and the mark could be distinguished well, Δ: there was a transfer but the mark could be distinguished, x: the mark peeled off and could not be distinguished.

  In addition, as an evaluation of the above dyeing property, the friction transfer method is such that the marked electric wire is fixed to a friction tester (conforming to the dyeing fastness test method for JIS L 0849 friction), and 30 reciprocations are performed with a white cotton cloth (cotton width). Friction was performed, and the state of transfer of the dye onto the white cotton cloth and the possibility of distinguishing the mark after friction were evaluated. The evaluation was performed in three stages: ○: white cotton cloth had no transfer and the mark could be distinguished well, Δ: transfer was available but the mark could be distinguished, x: transfer was intense and the mark could not be distinguished.

  Table 3 shows the results of these evaluations for the inks 1 to 9 of the examples and comparative examples.

  According to Table 3, it can be seen that the inks 1 to 6 of the above examples all have excellent marking clarity and dyeability, and excellent discrimination of the coated electric wires after marking. .

  On the other hand, the ink-7 and the ink-8 of the above comparative example were slightly insufficient in clarity and dyeability was insufficient. Ink-9 was clear enough, but dyeability was slightly insufficient.

  Thus, in this embodiment, the outer surface of the article can be marked by dyeing without forming a film of the film-forming resin on the outer surface of the article made of the polyvinyl chloride resin. It is possible to provide a marking ink having excellent discrimination.

  Further, in the present embodiment, the oil-soluble dye can be easily dissolved during the production of the marking ink, and the marking ink having good ink stability can be provided.

In carrying out the present invention, not only the above-described embodiment but also the following various modifications can be mentioned.
(1) As an article made of a polyvinyl chloride resin, in addition to the polyvinyl chloride resin-coated electric wire of the above embodiment, the entire article is formed of a polyvinyl chloride resin, for example, a bottle, a board, a sheet, It may be a film, tube, tape, cover or clip. Further, the outer surface of the article may be formed of a polyvinyl chloride resin, for example, a wire harness-related article such as a connector.
(2) As a method for applying the marking ink, in addition to the application by the ink jet method of the above-described embodiment, for example, the application by a roller, the application by dipping in a dip method, and the aerosol of the marking ink to be used with a pressurized gas It may be applied or applied by an ultra-micro discharge device such as a microdispenser or a microvalve that drops the marking ink in a droplet state.

Claims (2)

In the marking ink for marking the outer surface of an article made of polyvinyl chloride resin,
Contains organic solvents and oil-soluble dyes,
The solubility parameter of the organic solvent is δ1,
The solubility parameter of the oil-soluble dye is δ2,
When the solubility parameter of the polyvinyl chloride resin is δ3, the following formulas | δ1-δ2 | ≦ 2.0 (J / cm ³ ) ^1/2
| Δ1-δ3 | ≦ 2.0 (J / cm ³ ) ^1/2
| Δ2-δ3 | ≦ 2.0 (J / cm ³ ) ^1/2
Ink for marking, characterized in that   2. The marking ink according to claim 1, wherein the organic solvent contains acetone or methyl ethyl ketone having a volume fraction of 80% or more.