New Research On Pfer Printing Technology

Transfer printing of pigment or dye onto paper, rubber or other carrier and pfer it to the merchandise to be printed. It is called pfer printing, but in narrow sense, pfer printing refers to the pfer printing technology using needle textile as carrier.

Transfer printing is mainly used in polyester fiber products. With the improvement of pfer printing, it has been widely applied in nylon, acrylonitrile, cotton, hemp and woolen fabrics.

Transfer printing is divided into wet, dry, steam, vacuum and thermal methods.

The pfer printing method can reproduce the pattern accurately and facilitate the mechanized production. The process is simple, especially the printing postprocessing technology is simpler than the traditional printing and dyeing, and the printing feel is the same as that of printing and dyeing.

However, most printing and dyeing factories in China still use traditional printing and dyeing methods. Only a few production units use pfer printing for production.

At present, the widely used hot-melt resins include polyamide, vinyl acetate copolymer, polyurethane and so on.

Polyester hot melt adhesive is mainly composed of polyester resin and polyester resin is polybasic acid.

It was obtained by esterification with polyols.

Polyamido hot melt adhesive has strong adhesion, toughness, low temperature resistance and nylon fabric affinity. It is suitable for the preparation of nylon pfer printing paper.

The ethylene - vinyl acetate copolymer has low melting point and strong bonding force. It is suitable for the production of pfer printing paper after adding printing ink.

The polyurethane hot melt adhesive is mainly used for leather and polyhydrogen vinyl plastic glue.

Because of the difference in pfer printing, it is better to use suitable hot melt adhesive ink.

1. Characteristics of pfer printing

(1) the pfer printing pattern has the characteristics of realistic flower pattern, detailed pattern, clear level and strong three-dimensional sense.

Transfer printing can print natural scenery and artistic patterns.

(2) pfer printing equipment has the characteristics of simple structure, small occupation area, less investment and high economic efficiency.

Because the equipment is tension-free processing, it is suitable for printing various kinds of thick and thin sheets.

In addition, after pfer printing, the factory can be packed without postprocessing.

(3) there is no environmental pollution problem in pfer printing.

As dry process, no washing, steaming, drying and other processes, no exhaust and waste water discharge.

(4) pfer printing has the advantages of high production efficiency, labor-saving and easy operation.

Two, pfer printing mechanism pfer printing is mostly used in polyester fabric.

It is through high temperature (about 200 degrees) to dye heat sublimation for gas condensation on the surface of polyester, then to the amorphous region of fiber macromolecules, after cooling, fixed in the fiber printing method.

Three. The requirement of pfer printing for dyes, disperse dyes used in pfer printing, the sublimation temperature should be lower than the melting point of fiber macromolecules and the principle of no damage to fabric strength. The suitable temperature for polyester is 180--210 C.

In this temperature range, the molecular weight of dye sublimation is between 230--270.

There are three types of disperse dyes in this range.

Fast dyed disperse dyes: when the temperature is about 180 degrees Celsius, it can sublimate hair color, increase temperature and color change, and the edge will be seeping.

Good disperse dyes: the temperature can be sublimed at 180--210 degrees.

The hair color curve is flat.

It is a suitable disperse dye for pfer printing when it has little influence on temperature.

Late disperse disperse dyes: dyes can not sublimate and color well at 180--210 C.

If you increase temperature, you can get good hair color.

Such dyes are strongly dependent on temperature when they are dyed.

According to the above situation, the dyes applicable to pfer printing should meet the following requirements:

(1) the dyes for pfer printing must be sublimated below 210 degrees Celsius, fixed on fibers, and can obtain good washing fastness and ironing fastness.

(2) dye pfer printing can be sublimated into a gas dye macromolecule, heated on the surface of the fabric and diffused into the fiber.

(3) the dyes used for pfer printing are less affinities to pfer paper and have greater affinity for fabrics.

(4) dyes for pfer printing should be bright and bright.

Four. The printing of pfer paper for pfer printing of pfer paper is mostly printed and screen printing process and equipment.

The color ink consists of dyes, color carriers, adhesives and so on.

The preparation of the ink is to mix the above three components and pour them into the colloid mill or the three roller abrasive machine to make the dye evenly distributed in the ink.

(1) the carrier of the colorant is to distribute the dye evenly in the ink and pfer the dye from the printing equipment to the pfer paper.

Color carriers should be inexpensive, non-toxic and non flaming.

According to this requirement, water is most suitable.

But the pfer paper is made up of cellulose. When water is used as a carrier, the fiber will expand, resulting in the deformation of fine patterns, and because of the slow evaporation of water, it is difficult to produce at high speed.

For example, when using organic solvent color carrier, although the deformation of paper is small, the color ink can print fine patterns, and has the appropriate volatility, which is conducive to the advantages of higher speed production.

But it has the disadvantages of high cost and easy combustion.

Strict attention should be paid when using.

Oil color carriers, such as high boiling point oil, can also be used.

However, high boiling oil will cause dyes to diffuse to the deeper part of the pfer paper, thus affecting the amount of dye pferred from the pfer paper to the fabric.

(two) binder is the material that controls the viscosity of ink.

The amount of binder is too small to guarantee the viscosity of the ink, resulting in poor printing pfer paper and excessive amount of binder. The pfer speed of dye from the pfer paper to the fabric is slowed down, which results in too much dye left on the pfer paper.

The binder should be selected separately according to the different color carrier.

When water is used as a color carrier, synthetic gum or carboxymethyl cellulose is usually used as binder. When organic solvent or oil is used as a carrier, ethyl cellulose can be used as binding agent.

Five. Transfer printing requirements for pfer paper

Transfer printing used for printing pfer paper should have the following characteristics:

(1) enough strength;

(2) the affinity for color ink is small, but pfer paper has good coverage for ink.

(3) the pfer paper should not be deformed, crisp and yellowed during printing.

(4) pfer paper should have proper hygroscopicity.

Too bad hygroscopicity will cause the ink to color; excessive moisture absorption will cause the distortion of pfer paper.

Therefore, packing should be strictly controlled when producing pfer paper.

It is more appropriate to use half filler in paper industry.

According to the above requirements, the pfer paper should meet the following criteria:

Hygroscopic 40--100g/

Tear strength is about 100kg/5x20cm

Air permeability 500---2000l/min

Weight 60--70g/

PH value 4.5--5.5

Dirt does not exist.

Transfer paper is best made of needle leaf wood pulp.

Chemical pulp and mechanical pulp produce more than half of the pulp.

This ensures that the flower paper is not brittle and yellow when it is treated at high temperature.

Six. Printing method of flower paper

The printing of flower paper is the process of printing the pattern onto the pfer paper by means of printing and screen printing.

At present, most of pfer printing paper is printed by printing method.

There are four methods for printing flower paper, including gravure printing, letterpress printing, lithography and screen printing.

Printing technology is used to print flower paper, and gravure printing is the most widely used.

Screen printing method is suitable for printing small batch and multi variety pfer printing flower paper, and can make toilet paper in printing and dyeing factory.

It has the characteristics of low cost, fast speed, strong color and easy operation.

However, because of the use of water-soluble ink, the screen printing method has poor stereoscopic sense and outline definition on the flower paper, and the pattern is coarse, so that it can not display the characteristics of the pfer printing pattern.