GOST 34376.1-2017 Plastics. Thermoplastic polyurethanes for forming and extrusion. Part 1. Notation system

Product catalog Polyurethane TU 84-404-78

In the forties of the twentieth century, the famous German scientist Bayer Otto Georg Wilhelm first synthesized a urethane elastomer, which was destined to revolutionize technology. The public learned what kind of material it was, polyurethane, only 20 years later.

What it represents and why it’s good

A synthetic substance with a polymer structure, due to the mixing of components, is capable of acquiring various qualities. It can be plastic and rigid, and also have different coefficients of friction. Withstands stretching up to 500% and temperature changes from -60 to +80 degrees.

Plastic is an elastomer that can return to shape after deformation loads are removed. The basis is made up of long chains of macromolecules of the urethane group. Specific features are acquired by adding additional elements.

Designation of cuffs according to GOST 14896-84

An example of a symbol for a hydraulic cuff type 1 for sealing the gap between a cylinder with a diameter of 32 mm and a rod with a diameter of 22 mm, according to GOST 14896-84: Cuff 1-32x22 GOST 14896-84.

Polyurethane technical characteristics: chemical and physical properties

The main advantage of this type of raw material is the ability to give it a variety of qualities. As an elastomer, it retains its geometry perfectly and is able to return to its original state many times. According to this indicator, this material is ahead of its main competitor - rubber. Thanks to this, it shows high wear resistance.

What is polyurethane, the chemical composition of the material and properties

Main components:

polyols – long chains; diols – short; diisocyanates.

Due to the combination of components, the necessary elasticity qualities are imparted. The results are stable compounds that retain their parameters at different temperatures and are not inclined to react with the environment. Plastic retains its structure in the presence of: oils, acids, alkalis and fats. Does not undergo hydrolysis, resistant to microorganisms (fungi, bacteria, archaea). The substance easily tolerates moderate exposure to ultraviolet radiation. It is not oxidized by ozone like rubber. This increases the service life of products. Physical qualities

The main advantage is the ability to temporarily change the geometry and the ability to add a variety of additional properties. Products based on this material are used in various industries because it:

• able to return to its original shape after removing the force;
• shows high wear resistance;
• maintains quality factor during heating and cooling;
• does not allow electricity to pass through;
• has a thermal conductivity coefficient from 0.19 to 0.25 depending on hardness;
• creates an airtight film;
• has a relatively low specific gravity;
• It is possible to create parts with different transparency coefficients.

Preface

The goals, basic principles and basic procedure for carrying out work on interstate standardization are established in GOST 1.0-2015 “Interstate standardization system. Basic provisions" and GOST 1.2-2015 "Interstate standardization system. Interstate standards, rules, recommendations for interstate standardization. Rules for development, acceptance, updating and cancellation"

Standard information

1 PREPARED BY the Autonomous non-profit organization “Center for Standardization, Standardization and Classification of Composites” (ANO “Standartkompozit” with the participation of the Association of Legal Entities “Union of Composite Manufacturers” (“Soyuzkompozit”) and the Joint Stock Company “Institute of Plastics named after G.S. Petrov” (JSC “ Institute of Plastics") based on the official translation into Russian of the standard specified in paragraph 4, which was carried out by FSUE "STANDARTINFORM"

2 INTRODUCED by the Federal Agency for Technical Regulation and Metrology (Rosstan-

dart)

3 ADOPTED by the Interstate Council for Standardization, Metrology and Certification (protocol dated November 30, 2022 No. 52—2017)

The following voted for adoption:

4 By Order of the Federal Agency for Technical Regulation and Metrology dated December 12, 2022 No. 1913-st, the interstate standard GOST 34376.1-2017 (ISO 16365-1:2014) was put into effect as a national standard of the Russian Federation on June 1, 2018.

5 This standard is modified in relation to the international standard ISO 16365-1:2014 “Plastics. Thermoplastic polyurethanes for molding and extrusion. Part 1. Designation system and basis for specifications" (“Plastics - Thermoplastic polyurethanes for molding and extrusion - Part 1: Designation system and basis for specifications", MOD).

Additional phrases and words, indicators and their meanings included in the text of this standard are indicated in italics.

References to international standards IS011469 and IS01043-4 are excluded as they are for reference only.

The name of this standard has been changed relative to the name of the specified international standard to bring it into compliance with GOST 1.5 (subsection 3.6).

Information on the compliance of reference interstate standards with international standards used as reference in the applied international standard is given in Additional Appendix DA

6 INTRODUCED FOR THE FIRST TIME

GOST 34376.1-2017

4.2 Thermoplastic polyurethane (TPU) based on aromatic isocyanate (AR) and polyester polyol (ES), glass fiber reinforced (GF), injection molded (M), natural (undyed) (N), containing heat stabilizer (H) , anti-hydrolysis stabilizer (W), anti-oxidation stabilizer (O), having a hardness of 73 (75) and a tensile modulus of 2800 MPa (200), should be designated:

7

Appendix YES (reference)

Information on the compliance of reference interstate standards with international standards used as reference in the applied international standard

Types of polyurethane

The chemical industry produces three main classes.

Adiprenes

These are elastic substances with good shape retention characteristics. They are used to make protective boots, tire treads for automobile transport, gaskets and seals, rollers for carts and conveyors, coatings for gratings and components in the manufacturing industry. The parts are used in cyclones, screens and separators (to protect products from wear). Frames for casting are made from plaster and concrete.

Vulkollans

Due to its increased hardness and temperature range from -60 to +120 degrees, at which the parameters do not change, this material is necessary for creating supports, bushings, and silent blocks.

Vulcoprenes

These are the types that are used for subsequent vulcanization in combination with other polymers (rubber). Allows you to achieve high abrasion rates.

Specifications

The group has quite diverse properties depending on the molecular composition and manufacturing technology. This determines the prevalence of this raw material in different areas of life.

Peculiarities:

• Density ranges from 30 to 300 kg/m3, and is achieved using additives and production methods.
• It has a hardness of 40 to 98 units on the Shore scale. This allows you to expand the range of use.
• Polyurethane has a wide operating temperature range from -60 to +80 degrees. There are species that can not lose their qualities at 140℃.
• Elastic. Deformation up to 650% is possible.
• It has high resistance and can act as an insulator.
• The specific gravity is small, which makes the structure lighter.
• Not subject to destruction by nitrogen, like rubber.
• Resistant to hydrocarbon solvents (lubricating fats, kerosene, oil, diesel fuel, isooctane, petroleum ether).
• Reacts poorly to the presence of benzene and toluene. It swells with an increase in volume up to 60% and loses its technical characteristics.
• Has a different coefficient of friction. Programming is possible depending on need.
• Not susceptible to damage from microorganisms and fungi.
• It is possible to give different light absorption coefficients from transparent to black.
• It has good water resistance properties at room temperature.

Advantages and disadvantages

Depending on what polyurethane is made of, it has both positive and negative features.

The advantages include:

• Elasticity. According to this indicator, it confidently outperforms rubber.
• Wear resistance. Thanks to this quality, it is widely used in the shoe industry and in the manufacture of various wheels and rollers for warehouse equipment. On the MPlast website you can select the necessary products at an affordable price.
• The surface has a smooth structure, which allows it to maintain its presentation during use.
• Over time, the technical characteristics remain the same (not subject to aging).
• Resistant to most organic solvents.
• Insensitive to ultraviolet light.
• This plastic can be given a different coefficient of friction. Depending on the needs, it is possible to create a slippery surface or good grip.
• Easy to process. Allows casting, thermal molding, foaming and other methods.
• Does not allow air to pass through. Thin coating makes it airtight.
• Is a dielectric. 2 mm does not allow breakdown when 20 kilovolts are applied.

Disadvantages include:

• Instability to media containing aromatic hydrocarbons (benzene, toluene), as well as to some acids, turpentine and chlorine-containing compounds.
• Limited use in clothing and footwear due to breathability.
• Becomes brittle when exposed to low temperatures for a long time.
• Has complex recycling technology.
• Difficult to recycle.

Content

1 Scope………………………………………………………..1

2 Normative references……………………………………………………..1

3 Notation system…………………………………………………….2

3.1 General instructions………………………………………………………..2

3.2 Data block 1……………………………………………………….2

3.3 Data block 2……………………………………………………….3

3.4 Data block 3……………………………………………………….4

3.5 Data block 4……………………………………………………….5

3.6 Data block 5……………………………………………………….6

4 Examples of designations……………………………………………………….6

Appendix YES (reference) Information on compliance with reference interstate standards

international standards used as reference

in the applied international standard……………………………..8

Bibliography…………………………………………………………….9

IV

Where is polyurethane used?

Chemical plants produce this material in three forms: solid (sheet, rod, granular), fluid and foam. The first is used for the production of gaskets, protective cuffs, bushings, silent blocks and press seals. This substance has gained great popularity in the production of tubeless tires for sporting goods (roller skates, skateboards), for baby strollers, and technological equipment (trucks, electric cars, warehouse carts, guides for conveyors). These products are presented in a wide range in.

Liquid is used for sealed anti-corrosion coating of a wide variety of structures: concrete floors, roofs, screen surfaces, conveyor belts. It is used as a component in sealants, glue, varnish, and paint. During subsequent processing by vulcanization, complex protective elements are made from it: moldings and cuffs.

Foam is used for insulation of buildings and technological devices. It produces light and elastic soles for sports shoes and light-duty tires. It is not possible to list what is made from polyurethane. This material is widely in demand:

• In heavy industry, where vibration stands are used, and where the use of conditionally movable units is necessary.
• In the construction industry. They insulate the surfaces of buildings and create a film that protects against atmospheric influences.
• In the automotive industry. It is used to make tires, silent blocks, cuffs and gaskets, and protective covers.
• In medicine. It became widespread because of its neutrality. The products do not emit harmful substances and do not react with medications. Flexibility and high wear resistance allow it to be used in the preparation of prostheses, condoms, implants and coatings for equipment (crutches, beds, handrails, wheelchairs).
• In the furniture industry. Used in the production of mattresses, garden furniture, fasteners, chairs and tables, elements for decorative finishing.
• In the manufacture of sports accessories: treadmills, rollers, restraints in exercise machines, sneakers and sneakers, anti-slip coatings, impregnation of covers.
• In light industry. The material is used to make shoe soles, rivets, bathroom rugs, and orthopedic insoles. Fabric imitating genuine leather is produced.

Comparative characteristics of rubber and polyurethane

Foamed PU (foam rubber)

It is a porous synthetic product gas-filled with 85-90% inert gas. Depending on the production method and composition, it differs in the degree of elasticity. It can be either soft (foam rubber) or hard, which is almost not subject to deformation.

Two-component polyurethane foam - PU foam, which is formed by mixing two components, is widely in demand in industry and construction. The reaction proceeds very quickly - within 5-10 seconds the polyurethane foam foams and then hardens. The result is a light mass with low thermal conductivity, which does not rot, does not support independent combustion, and is not exposed to moisture, alkalis, organic solvents, or weak acids. Foamed polyurethane foam is in great demand as insulation and sound insulation. Perfectly fills pores, thereby preventing the formation of cold bridges. It is used in a wide temperature range from -60°C to +140°C, and practically does not change its properties over time.

What and how is polyurethane made from?

The initial raw material for production is oil. It produces two main components - isocyanate and polyol. Their percentage composition, as well as the presence of additives, determine the physical properties of the final product. The result can be a solid, liquid or viscous substance suitable for further processing, like a regular polymer.

The fiber leaves the plant for processing in the form of granules, rods, sheets or in a liquid state. Initially, the appropriate color and degree of transparency are given. These types of supplies allow us to use simple technological solutions to produce certain products needed by the consumer.

Forming methods

The buyer requires a functional product that has certain properties. To achieve this, processing methods are used that are similar to those used with all plastics.

Extrusion

Polyurethane polymer is excellent for injection molding. Under pressure, the heated and softened material is fed into the outlet of the extruder. Hardening occurs in this same zone. As a result, the output is a rod with a given cross-section or a flat sheet. The resulting rolled product is cut or rolled into rolls.

Casting

This method is the most common. It is used to manufacture products with complex geometries: bushings, supports, cuffs, seals, hydraulic elements and bearings. The advantage is easy automation of the process and the ability to produce large batches. For the manufacture of piece parts, the dimensions of which can be up to several tons, casting is used on a bench. The softened mass is poured into the frame, followed by hardening and acquiring a stable shape.

To speed up the process, increased pressure is used in automatic lines. The method differs little from the technology of products made from any plastic. It is often necessary to coat a metal workpiece with polymer. Then softened polyurethane is applied manually or under computer control to the item. As it cools, the layer becomes elastic and creates a protective film.

Pressing

The prepared material (sheet, rod or granular) is fed to the apparatus, where it is shaped using extreme pressure in a limited space. The process may be accompanied by preheating or softening of the substance due to compression. This produces a part with changed properties and a clearly defined geometry. In production, this action is controlled using software.

Fill

To produce artistic or piece goods, the natural casting method is used. Liquid material is placed manually into the prepared mandrel. Under the influence of high temperature or reagents, the device freezes, maintaining the required configuration. In this way you can make a small series of any blanks. More often used for the manufacture of large forms and decorative elements.

Structural laminate

Unlike getinax (laminated paper-based plastic), textolite is a multilayer material based on cotton fabrics impregnated with an alcohol solution of phenol-formaldehyde or cresol-formaldehyde resin, made by hot pressing.

For each grade of textolite, fabrics of different densities and weaves are used. The nature of the weave affects the degree of tensile strength of the final material, impact strength, and resistance to cracking.

As a rule, chiffon, calico, calico, and belting are used for production. The process of producing textolite includes preparing an alcohol solution of resin, which is placed in a special bath, where it is maintained at a constant temperature of 30–40˚C.

The fabric, previously fixed in a mandrel, is lowered into the bath, after which it is passed through the rollers. As a result, the resin solution is distributed more evenly, and the fabric is sent for drying. During the drying process at 120˚C, excess moisture, alcohol, and volatile phenol are removed.

The dried fabric is cut, put into bags and loaded into a press, where they are first heated to a certain temperature, maintained and cooled under pressure.

The finished material is cut to create a straight edge line and, after technical control, is delivered to the finished product warehouse.

The main advantages of the composite compared to conventional plastics are its high degree of heat resistance and strength.

Composite material is more elastic and wear-resistant than metal. In addition, it is easy to process, and products made from it do not require painting. It is fireproof, resistant to gasoline, technical oil and water. Non-toxic.

Recycling

Resistance to weathering and aggressive environments is a challenge when recycling urethane elastomers. Under natural conditions, they do not decompose for decades. The ability to resist ultraviolet radiation and ozone makes this type of plastic a perpetual polluter of the environment. Therefore, the issue of recycling has become acute.

There are several methods to solve the problem:

• 
  Burning. Like all hydrocarbons, the polymer is highly susceptible to high-temperature oxidation. But technological additives contain substances that are hazardous to the environment. During combustion, decay products enter the atmosphere.

• Physical method. Crushed products have found application in construction, as an additive to concrete and asphalt. Due to this, they acquire a second life.
• Remelting. When heated, the waste is given the required shape and put back into circulation. The disadvantage of this method is that it is difficult to obtain a product with clearly defined characteristics from dissimilar components.
• Glycolysis is the process of breaking down long molecules at high temperatures in the presence of catalysts. The output is short molecular compounds, which subsequently find service in industry (production of paints, varnishes, additives in asphalt concrete).
• Chemical method. This is the splitting of chains using reagents. The goal is to obtain a substance suitable for further use.
• Uniqueness and interesting facts about the use of polyurethane
• The ability to give a material a variety of characteristics has allowed it to appear in many industries. When playing sports, we use products made from this polymer. Clothes, shoes, and medical equipment are made from it. Modern transport (cars, airplanes, railway cars) have long used the unique properties of this substance. Its invulnerability has become an environmental problem. A few years ago, a species of fungus was discovered that requires the presence of this plastic to survive. Pestalotiopsis microspora successfully decomposes polyurethane and can be eaten. Gourmets claim that it tastes like bread. Maybe in the future this will be a solution to the recycling problem.