JPH04225072A - Liquid pigment - Google Patents

Abstract

PURPOSE:To provide a liquid pigment for dope dyeing yarns having good operability by eliminating factors dispersing yarn quality resulted in liquid pigments and thus worsening operability. CONSTITUTION:According to the present invention, in a liquid pigment being liquid at ordinary temperature and having 500-2000 poise viscosity at 25 deg.C, a liquid pigment characterized by <=300% coefficient of cubic expansion at 7.6mmHg is exemplified. The coefficient of cubic expansion is expressed by the following formula: Coefficient of cubic expansion =V1/V0X100% [wherein V0 represents the volume when a liquid pigment is put in a definite vessel at ordinary pressure (1 atom) and V1 represents the volume when pressure in the vessel is reduced by sucking with a vacuum pump and the pressure becomes 7.6mmHg expressed in terms of gauge pressure].

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to liquid pigments for raw materials using a thermoplastic synthetic polymer as a dispersant (vehicle).

0002

BACKGROUND OF THE INVENTION Since dyed yarns have the advantage of omitting the dyeing process, they have been widely used for general clothing and industrial materials. In addition, since dyed yarns are excellent in terms of light fastness, the demand for them has been increasing in recent years. by the way,
In these general clothing and industrial material applications, it is rare for only a single color to be used, and the production of dyed yarn in a variety of colors is required, and as a solution to this, the masterbatch blending method has been widely adopted. It has been.

[0003] However, this masterbatch method
This method requires cleaning of the supply system, extruder, and conduits of the melt-spinning machine when changing colors, which has the drawback of reducing productivity. Therefore, instead of using this masterbatch method, we decided to use a liquid pigment dispersant (hereinafter referred to as
The so-called injection method is mainly used for polyester fibers, in which a liquid pigment (referred to as "liquid pigment") is supplied from the middle of the melter (for example, from the melt pack section) to change colors without contaminating the extruder or conduits with pigment dispersant. (For example, JP-A-58-149311, JP-A-60-45689, JP-A-60-45)
690, JP-A-63-117071, etc.).

0004

[Problems to be Solved by the Invention] However, when these liquid pigments according to the prior art are added by injection into a molten thermoplastic synthetic polymer such as polyamide, polyester, polypropylene, polyvinylidene chloride, etc., there is a problem in operability. I understand. The liquid pigment dispersant used here is usually a liquid aliphatic polyester or aromatic polyester, but when pigments and various additives are added to this to form a liquid pigment, the viscosity thereof usually increases. In particular, when the pigment concentration is increased or a pigment with a large oil absorption amount is used, the viscosity becomes 500 poise or more, sometimes 1,000 poise or more.

By the way, using such a liquid pigment,
When spun-dyed yarn was produced, close observation revealed that a lighter colored portion appeared along the length of the yarn in the hand direction. Also, sometimes
It was also found that there was a problem in that the spinning condition deteriorated and spun yarn breakage occurred frequently.

An object of the present invention is to provide a liquid pigment for spun-dyed yarn that has excellent workability by eliminating the factors that cause variation in yarn quality and deterioration of workability caused by the liquid pigment.

[0007]

[Means for Solving the Problems] According to the present invention, in a liquid pigment that is liquid at room temperature and has a viscosity of 500 or more and 2,000 poise or less at 25°C, the volume expansion coefficient when the pressure is reduced to 7.6 mmHg. Provided is a liquid pigment characterized in that: 300% or less.

[0008] The above volumetric expansion rate is expressed by the following formula.

[0009] Volumetric expansion rate = V1/V0×100 (%
) [Here, V0 is the volume when the liquid pigment is placed in a certain container at normal pressure (1 atm), and V1 is the volume of the liquid pigment after the pressure inside the container is reduced by suction with a vacuum pump to 7.6 mm in gauge pressure.
It represents the volume when it becomes Hg. ] The pigment dispersant (vehicle) used in the present invention is a polyester or polyether ester that is liquid at room temperature, and these may be used alone or in combination. In some cases, it can also be used in combination with other dispersants.

The above-mentioned liquid polyester is mainly made of aliphatic dicarboxylic acids or alicyclic dicarboxylic acids such as adipic acid, sebacic acid, azelaic acid, glutaric acid, and hydrogenated phthalic acid, and ethylene glycol, propylene glycol, butylene glycol, etc. It is the result of a polycondensation reaction with glycol.

[0011] The aliphatic dicarboxylic acid has 3 to 3 carbon atoms.
No. 8 is preferable, and among them, adipic acid is the most preferable. In addition to the above dicarboxylic acids, acid components include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, and orthoisophthalic acid, or monovalent carboxylic acids such as coconut oil fatty acids, oleic acid, and lauric acid, trimellitic acid, Trivalent or higher polycarboxylic acids such as pyromellitic acid may be used in combination as appropriate.

The glycol component preferably has about 2 to 6 carbon atoms, with propylene glycol and butylene glycol being particularly suitable. In addition to glycol components, monohydric alcohols such as n-octyl alcohol, isooctyl alcohol, and n-nonyl alcohol,
Alternatively, polyhydric alcohols such as glycerin, pentaerythritol, and sorbitan can be used as appropriate.

[0013] The liquid polyether ester, which is another pigment dispersant used in the present invention, is the following repeating unit (chemical formula 1) obtained by polycondensation reaction using dicarboxylic acid and polyoxyalkylene glycol as main components. A polymer consisting of

[0014]

[Formula, R' is an alkyl group having 2 to 15 carbon atoms, R'' is an alkyl group having 1 to 7 carbon atoms, and n is an integer of 2 to 20.] Here, the dicarboxylic acid is Examples include aliphatic dicarboxylic acids such as malonic acid, succinic acid, adipic acid, pimelic acid, azelaic acid, and sebacic acid, and aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, and naphthalene dicarboxylic acid. Among them, aliphatic dicarboxylic acids having 3 to 8 carbon atoms are preferred, and adipic acid is most preferred.

Examples of the polyoxyalkylene glycol include poly(oxyethylene) glycol, poly(oxypropylene) poly(oxyethylene glycol), and the like. In addition, the molecular weight of these is 2,000
Below, it is preferably about 80 to 1,000. Furthermore, from the viewpoint of heat resistance, it is also possible to advantageously select a low molecular weight glycol component such as diethylene glycol or triethylene glycol.

The number average molecular weight of these dispersants themselves is preferably 1,000 to 8,000, more preferably 1
,500 to 5,000. If it is less than 1,000, problems tend to occur in terms of heat resistance, while if it exceeds 8,000, the viscosity becomes high and it becomes impossible to increase the mixing ratio of pigments, making it difficult to obtain the desired coloring.

Pigments used in the present invention include commonly used organic pigments such as azo, phthalocyanine, perylene, and anthraquinone, and inorganic pigments such as carbon black, red iron, ultramarine, and titanium oxide. However, the pigments are not particularly limited to these, and in some cases, a combination of these pigments or a combination of a pigment and a dye may be used.

In the present invention, the ratio of the pigment to the pigment dispersant is 30 to 300 parts by weight per 100 parts by weight of the pigment.
0 parts by weight, preferably 50 to 2,000 parts by weight. If the pigment dispersant is less than 30 parts by weight, the viscosity of the liquid pigment becomes too high and it becomes difficult to handle;
If it exceeds 0 parts by weight, the coloring power will be poor and the amount of dispersant will be too large, resulting in poor thread-spinning properties.

When a pigment is added, the viscosity of the liquid pigment for base use may be in the range of 500 to 2,000 poise at 25°C. If it is less than 500, the pigment and pigment dispersant will be easily dispersed, while if it exceeds 2,000, it will be difficult to handle and productivity will decrease. Of course, the premise is that this liquid pigment is liquid at room temperature (usually around 25°C to 30°C).

[0020] In such a liquid pigment, the feature of the present invention is that the liquid pigment is heated to 7.6 mmH.
The reason is that the volumetric expansion rate when the pressure is reduced to 300 g is adjusted to 300% or less. This volumetric expansion rate cannot be seen from the outside, but it can be said to be a quantitative expression of the phenomenon in which gases, bubbles, etc. are trapped in the liquid pigment and expand due to reduced pressure.

The significance of this "volume expansion rate of 300% or less" will be explained in detail in the [Operation] section.

The liquid pigment for polyamide base use of the present invention can be prepared, for example, by mixing a dispersant, each pigment, and other additives, and dispersing and mixing the mixture using a kneader.

[0023] The OH value of polyether/ester or polyester as a dispersant is 30 to 120 mg/K in order to improve the dispersibility in the substrate polymer.
It is preferable to control the amount of OH/g, preferably 35 to 80 mg·KOH/g. OH value is 30mg・K
If it is less than OH/g, it cannot be used for general purposes as a pigment dispersant, while if it exceeds 120 mg KOH/g, problems will arise in terms of heat resistance.

Further, in the case of polyester, this control of the OH value can be achieved by adding an excess of alcohol (glycol) component to the acid component, or by increasing the ratio of polyhydric alcohol. For example, by selecting a range of 1.1 to 2.0 mol, preferably 1.2 to 1.5 mol, of the alcohol (glycol) component per 1 mol of the acid component, the desired product can be easily prepared.

The liquid polyester obtained in this way can be modified to adjust the viscosity or improve the dispersibility. For example, the liquid polyester can be bonded by adding disocyanates that easily react with OH groups. For example, how to

Examples of the diisocyanate include 2,4-tolylene diisocyanate and hexamethylene diisocyanate.

On the other hand, in the case of polyether ester,
As with the liquid polyester, this can be achieved by adding an excess amount of the glycol component to the acid component.

In order to adjust the OH value, in addition to the polyoxyalkylene glycol component, monohydric alcohols such as n-octyl alcohol, isooctyl alcohol, n-nonyl alcohol, ethylene glycol, 1,3 - Dihydric alcohols such as propylene diol and 1,4-butanediol, and polyhydric alcohols such as trimethylolpropane, glycerin, pentaerythritol, dipentaerythritol, and sorbitol can also be used as appropriate.

In order to produce spun-dyed yarn using the liquid pigment of the present invention, the liquid pigment is injected and supplied into the molten polymer conduit using a gear pump and kneaded using a static mixer, and then kneaded using a static mixer. What is necessary is to discharge it from a die, cool it, stretch it, and process it.

The dyed yarn thus obtained contains 0.01 to 2% by weight, particularly 0.1 to 1.0% by weight, as a pigment component in the yarn.
5% by weight, up to 6% by weight as a pigment dispersant, especially 0.1
Preferably, the content is 3.0% by weight. If the content of the pigment component in the spun-dyed yarn is less than 0.01% by weight, the coloring power will be poor and the characteristics of spun-dyed yarn will not be exhibited, while if it exceeds 2% by weight, the spinning properties will be poor. On the other hand, if the content of the pigment dispersant in the spun-dyed yarn exceeds 6% by weight, the spinning properties will be poor.

[0031]

[Function] As mentioned above, liquid pigments tend to have higher viscosity because the pigment concentration is increased or pigments with higher oil absorption are used. When spun-dyed yarns were produced using these liquid pigments, color spots and yarn breakage occurred, but the causes of this have not yet been analyzed. As we evaluated liquid pigments with various viscosities, we found that liquid pigments with relatively high viscosity and low fluidity were more prone to this problem. Especially when the viscosity is 500 poise or more, especially 1
,000 poise or more, this tendency becomes more pronounced. Further, when the yarn discharged during melt spinning was carefully observed, there was a possibility that something like air bubbles were present when yarn breakage occurred.

[0032] The inventors of the present invention have investigated various means for solving the problem based on these findings. As a result, the inventors have found that there is a mass of air bubbles in the liquid pigment, which causes the flow of the liquid pigment to become non-uniform. We have learned that sometimes there is a temporary interruption in supply. If we observe this phenomenon more clearly, we can see that the liquid pigment is heated to normal pressure (760mm).
It has been found that this problem occurs frequently when the volumetric expansion rate exceeds 300% when the pressure is reduced to 7.6 mmHg (1/10 atmosphere).

Generally, liquid pigments with high viscosity, particularly thixotropic liquid pigments with low fluidity, tend to entrain air bubbles, and once entrained air bubbles are presumed to be difficult to remove. Until now, we have used highly viscous liquid pigments, whose volumetric expansion rate under 7.6 mmHg is 3.
There was no idea that improved operability could be obtained by specifying it to be 0.00% or less. To remove air bubbles and gas from a liquid pigment, it is sufficient to apply a strong surface shear to the liquid pigment and apply vacuum suction. As a means of applying surface shear, there is a method of kneading with a roller mill or the like. To remove bubbles in a static environment, it is necessary to spend time in a high vacuum. In any case, as a liquid pigment, 7.6 mmHg
Stable operability and high quality (elimination of color spots) cannot be ensured unless the material is defoamed until the volumetric expansion rate under the pressure is 300% or less.

[0034]

[Example 1] The present invention will be explained in more detail with reference to Examples below. Adipic acid 1 as a vehicle for liquid pigments
Polycondensation was carried out in a conventional manner at a ratio of 1.3 moles of 1,4-butylene glycol to 1 mole of 1,4-butylene glycol to obtain a number average molecular weight of 2300 and an OH value of 45 mg. A liquid polyester of KOH/g was obtained. To 70 parts of this vehicle, an organic pigment (2 parts of phthalocyanine blue) and an inorganic pigment (27 parts of cobalt blue, 1 part of carbon black) were mixed to give a pigment concentration of 30% and a viscosity of 1.
A liquid pigment of 200 poise was prepared. A three-shaft roll mill was used to mix and knead the vehicle and pigment. When this conventional liquid pigment was vacuumed to 7.6 mmHg, its volumetric expansion rate was 1100% (conventional example).

On the other hand, with a device that was devised to be able to suck this liquid pigment under high vacuum while stirring it with a planetary mixer, the volumetric expansion rates at 7.6 mmHg were 400%, 280%, 130%, and 1.0 mmHg, respectively. A spinning test was conducted by preparing a sample in which gas was suctioned to remove air bubbles until the volumetric expansion rate reached 130%. During melt spinning of polyamide (nylon-6), 1.5% of these liquid pigments were added to the pack section directly above the spinneret via a 40-stage static mixer.

These samples were evaluated for spinability during melt spinning (bubble breakage) and color unevenness in the longitudinal direction of the yarn. As shown in Table 1 below, only the samples satisfying the volumetric expansion rate of the present invention exhibited good operability.

[0037]

[Table 1]

[0038]

[Example 2] 0.5 mol of ethylene glycol and 0.8 mol of diethylene glycol were added to 1 mol of adipic acid for polycondensation, and the number average molecular weight was 2,400.
A liquid polyether ester with an H value of 40 mg·KOH/g was obtained and used as a vehicle for liquid pigment. In this vehicle, carbon black = 1.0%, titanium yellow = 31.0%, Bengara = 4.0%, cyanine blue = 4
．． 0% (total pigment concentration = 40%) was added, stirred in advance with a high shear mixer, and then kneaded with a 3-shaft roll mill to obtain a liquid pigment. The viscosity of this liquid pigment at 25°C was 1440 poise.

[0039] This liquid pigment is used as it is on nylon-6.
When used as a coloring agent for polymers, the above liquid pigment is filled into a tank before use, taken out from the bottom of the tank with a plunger pump, spread in a thin film on the top of the tank, and returned while circulating. A vacuum pump was used from the top of the tank to change the degree of vacuum and the suction time to defoam the bubbles contained in the liquid pigment to prepare a sample for use in the present invention.

[0040] The degassing conditions and 7.6 mmHg from 1 atm.
The relationship between this and the volumetric expansion rate when the pressure is reduced to 1.0 mmHg is shown in the table below.

[0041]

[Table 2] Next, add nylon-6 polymer to 250% using an extruder.
It was melted at 0.degree. C., distributed to four gear pumps, weighed, passed through a pack and a spinneret, and spun into a 1300 denier, 68 filament yarn, which was then directly drawn and crimped. At that time, the molten polymer and the separately supplied liquid pigment were mixed and kneaded using a pack in which 40 stages of Kenix-type static mixers were installed. The liquid pigment was measured to be 2 wt % with respect to the nylon polymer using a gear pump that supplied a fixed amount of liquid pigment before each pack, and was directly supplied to the pack. The spinning process condition and color unevenness at that time are shown in Table 3.

[0042]

[Table 3]

[0043]

[Effect] The present invention has excellent handling properties in actual operation by controlling the gas and bubbles in the liquid pigment to below a certain level using the volumetric expansion rate under reduced pressure as a guide.
With this, we succeeded in providing a liquid pigment that could be truly put to practical use.With this, we were able to create spun-dyed yarn with no color unevenness in the longitudinal direction, with excellent operability and no concerns about yarn breakage. be.

Claims (4)

[Claims] [Claim 1] Liquid at room temperature, viscosity at 25°C is 5.
1. A liquid pigment having a volume expansion rate of 300% or less when the pressure is reduced to 7.6 mmHg in a liquid pigment of 00 poise or more and 2,000 poise or less. 2. The liquid pigment according to claim 1, wherein the dispersant is a liquid aliphatic polyester. 3. The liquid pigment according to claim 1, wherein the dispersant is a liquid aliphatic polyetherester. Claim 4: The OH value of the dispersant is 30 to 120 mg.
The liquid pigment according to claim 1 or 2, which is KOH/g.