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Методические указания по выполнению семестровой контрольной работы с комплектом заданий по английскому языку студентов дистанционной формы обучения Уфа 2007

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6. Dry-cleaning with a solvent alone is not so successful in removingng soil. Considerable effort has been devoted to improving clearing efficiency, leading to the use of solvent-soluble soaps and detergents, together with small amounts of water. In the "batch" method a soap or detergent is used to prepare a water insolvent emultion, a small quantity of which is added to the solvent in the machine with each load of garment.

7, The quantity of water added in this way ie very small, usually
no more than one per cent of the weight of the textiles and moat
of it is rapidly transferred to them. Added water raises the ef­
fective moisture content of the textiles to the optimum for ef­
ficient cleaning and eliminates the development of static electri­
city, but care has to be taken to prevent the moisture content
becoming too high. The detergent plays some part in improving
cleaning efficiency, but its effect ia greatly increased by the
water. All dry-cleaning processes have a number of common features
regardless of the type of solvent used.

8. After dry-cleaning it is frequently necessary to subject gar­
ments to a local spotting treatment to remove stains that have
proved resistant to the treatment in the solvent, in spite of the
improvements in dry-cleaning technique brought about by the use

of charged systems. The majority of these stains are food or other water-borne stains, which are removed by simple treatment with water. In addition, the use of more complex methods may be nece­ssary to remove the large variety of extraneous substances which accidently come into contact with garments during wear. Finally, garments are finished by atearn pressing or by ironing.
  1. thereby avoiding difficulties - чем устраняются трудности

2.solvent-soluble soaps -* растворяющееся в растворе мыло

3. moisture content - содержание влаги

Answer the following questions:
  1. What is the basis of dry-cleaning?
  2. How does the solvent act?
  3. What solvents are used in the dry-cleaning?
  4. What solvent is now predominant?
  5. How many per cent of all dry-cleaning is carried out with
    perchlorethylene, white spirit and trichlorethylene?
  6. What improvee cleaning efficiency?
  7. What is per cent of water added in this process?
  8. Why is it necessary to subject garments to a local spotting?
  9. What is the nature of the majority of stains?

10. How are garments finished?


Вариант II

Colour Fastness

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I. Large quantities of textiles in the form of garments and house­hold and furnishing fabrics are regularly dry-cleaned. In fact, dry-cleaning is the only suitable way of cleaning many types of materials. The question of colour fastness to dry-cleaning is therefore of considerable importance.
  1. Although most dyed and printed fabrics have adequate fastness
    of dry-cleaning, a few have only poor fastness and it is desirable
    that there should be reliable method of enabling an accurate fore­
    cast to be made of the performance of a coloured textile on com­
    mercial dry-cleaning.
  2. Until recently, there was no test for fastness to dry-cleaning.
    In the аdsеnсе of a specific test, there was a tendency to use the
    fastness to organic solvent when it was desired to access dry-
    cleaning performance. But then, there has been considered the
    question of colour fastness to dry-cleaning and to develop a
    suitable method of test.
  3. It ia considered that the colour fastness of textiles to dry-
    cleaning is influenced by the following features of dry-cleaning
    process - a )the solvent, b) mechanical action, c) the detergent.
  4. Mechanical action - has an important bearing on colour fastness
    particularly on prints and surface-decorated fabrics. The movement
    of garments against one another during cleaning produces a rubbing
    or frictional effect. Mechanical action in the cleaning process
    leads to loss of colour in the following way.

6. I . If a dye or pigment is to some extent soluble in the solvent mechanical action may increase or accelerate the dissolution by bringing the surface continuously into contact with fresh solvent and by assisting the detachment of pigment particles and their dispertion in the liquid phase.
  1. II . With pigment prints, if the binder may be softened but not
    dissolved to the solvent, the pigment becomes less firmly attached
    to the substrate and so becomes euspectible to removal by the ac­
    tion of rubbing and flexing, though loss does not occur in the
    absence of rubbing.
  2. III. With conventional prints, even with dyes normally of high
    fastness and where there is no question of solubility in the
    solvent but where the dye is predominantly on the surface of the fibre, loss can occur owing to the dye being rubbed off . Again, such loss does not occur in the absence of rubbing.
  1. IY. When there пав been poor penetration of the dye into the
    fibre, an apparent change of colour may be noticed although there
    has actually been no loas of dye either by dissolution or by phy­
    sical removal or rubbing.
  2. This effect is caused by slide displacement of the surface
    fibres by mechanical action with the result that undyed or paler
    parts of the fibre become exposed on the surface. This effect is
    often seen on fairly heavy and closely woven cotton cloth that
    have been piece-dyed. The effect is produced by any type of rub­
    bing. Those parts of garment that receive most rubbing in wear
    show colour loss to a prononced degree, whether or not they have
    been dry-cleaned.



  1. Colour fastness - цветостойкость
  2. dyed and printed fabrics -однотонные и набивные ткани
  3. loss can occur owing to the dye being cut off - потеря цвета
    может произойти вследствие стирания красителя
  4. show colour 1оза to a prononced degree -потеря цвета заметна в
    значительной степени

Answer the following questions:
  1. What fabrics are regularly dry-cleaned?
  2. Which is the only way of cleaning many types of materials?
  3. Why ia colour fastness of considerable importance?
  4. What has an important bearing on colour fastness?
  5. What produces a rubbing action?
  6. How does mechanical action effect the loas of colour?
  7. What can you say about the firat reason of colour loss?
  8. How do you explain the second reason of colour loss?
  9. What can you say about the third reason of colour loss?

10. Has dissolution or rubbing any importance in the fourth
reason of colour loss?


Вариант III

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Stripping Dyestuffs from Textiles1


и

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1. The knowledge how to partially or completely remove dyestuffs from various fibres might be considered as an important task for ill dyers.

2. Stripping may be necessary for any of several reasons such as incorrect shade, the dyeing being very deep or too far off tone. The primary requirement of a successful stripping methods are: a). The process must effectively remove the dyestuff; b). The fibre must remain substantially unimpaired so that it can be redyed; c). The cost factor must be justified. Often with off-runs it is best to cut the losses and dye the goods bleach.

3. It needs to consider a few basic fundamentals common to any tripping system. First of all, it may not be necessary to destroy colour but to merely reduce the depth of the tone. This is de-fined аз "back stripping" . In cases where the dyestuff is chemicaly attached and destroyed, the process is called destructive tripping . For back stripping the colour must be solluble or con­verted to a form which is solluble in the stripping medium which for all practical purposes is water.

4. Anthraquinone dyes are generally best attached in an oxidizing I urn. In practice, the hydrosulphites and aulphonylates are the common reducing agents used in industry. The net effect is bo make the dye-effect complex more accessible to the stripping btth and so promoting removal of dyestuff while an addition of polyvinil pyrrolidone is beneficial when stripping back deep shades.

5. The temperature of back stripping is quite critical, the grearemoval of colour generally ocouring around 180-190 P and if the temperature is raised to the boil the colour is generally iferred back to the fibre from the stripping bath. The addition of polyvinil pyrrolidone often helps this compound acting as ervoir for the colour leached away from the fibre. As with all back stripping techniques after the bath reaches equilibrium no further colour is removed frorc the fibre and if further reduc-of the shade is required the process must be repeated.

6. For reason of improved fastness to wet treatment increasing Lies of nylon are being dyed with both level and acid milling dyes. Рог back stripping nylon one follows a pattern of at­tach similar to that used for the same dyes on wool except the colour is more tenaciously is held by nylon.

7. There are some characteristics of the chemical nature of the various auxiliaries used in stripping methods. Dianyl W-75 ia re­presentative of that class of non-ionic dyeing auxiliaries with moderate affinity for dyestuffs and has a cloud point of 2IO-2I5'F in i per cent solution. Iguafen SS is essentially in the same group but has higher affinity for antoric dyestuffs. A newer va­riation and most useful type is found by combining a mildly catio-nic and a non-ironic group together in one molecule. Compound with high absorptive affinity for dyestuffa are represented by polivi-nyl pyrrolidone commercially known as Iguafen A which may be con­sidered a scavenger liquid fiber able to attract and absorb many dyestuffs.

Stripping dyestuffs from textiles - обесцвечивание тканей

back stripping - частичное обесцвечивание

destructive stripping - дистрактивное обесцвечивание

scavenger - удаляющий отработанные вещества

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Answer the following questions:
  1. What task is considered as an important task for all dyers?
  2. What are requirements of successful stripping?
  3. What can you say about "back stripping" and destructive
    stripping?
  4. What is the necessary condition of nback stripping'1?
  5. In what medium are anthaquinon dyes best attached?
  6. What role does the temperature play in removing colour?
  7. When ie it required to repeat the process?
  8. When are both level and milling dyes used?
  9. What characteristics of Dianyl and Iguafen SS can you name?
  10. 10.What is Iguafen A?


Вариант IV

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Natural and synthetic rubber

I. Apparently rubber was first discovered by natives in Central andSouth America. They used it as waterproofing material. Samples of this material were carried back to Europe by early explorers: it was soon found that small pieces of the elastic substance were handy for erasing pencil marks and thus it was given the name"rubber" .

2. Although rubber can be found in the milky fluid of certain plants, its chief source is the latex obtained from the rubber tree.

3. Natural rubber is a thermoplastic material that becomes soft and sticky when heated and hard when cooled. Prior to 1839,these roperties were responsible for many disappointing results in the manufacture of raincoats and other waterproof textiles. In experi­ments designed to improve the properties of rubber, Charles Coodyear, in 1839, accidently spilled a mixture of rubber and sulfur on a hot stove and discovered the process he later called vulcani­sation. Chemically, vulcanization involves a reaction of sulfur with the double bonds of the rubber molecules producing cross linkages of sulfur between adjacent chains of hydrocarbons. A soft

rubber is produced when the sulfur content is kept around 2 per cent, while extensive cross-linking, which occurs when around 30 cent of sulfur is used, resulte in hard rubber.
  1. The modern rubber industry has developed many special types of rubber for various purposes and has improved the quality by conious research. More recent research by the rubber industry in­volves vulcanization by radiation with gamma rays. Not only many ler articles, but also full-sized automobile tire have been riized without the uae of heat or curing agents .
  2. As isoprene was referred to natural rubber several chemistsed the polimerization of isoprene. It was that sodium cata-d the polymerization of the compounds and products with properties similar to rubber could be synthesized. The two main drawbacks to industrial development of synthetic rubbers were the high cost of synthetic rubber and the inferior quality of the synthetic product. One of the first synthetic polymers to compete with natural rubber was Neoprene, it possessed properties that made it lesirable than rubber for certain purposes.



  1. Neoprene is a polymer of chloroprene which is synthesized from
    acetylene. The most outstanding property of Neoprene is its resis­
    tance to heat, light, oils and chemicals. Аs the cost of Neoprene
    is about twice that for natural rubber, it is used wherever resis­
    tance to oxidation and chemicals is important.
  2. Several types of synthetic polymers were investigated with a
    view toward mass production to supply the large quantities of rub­ber needed. At present, a synthetic rubber composed of 80 per cent
    butadiene and 20 per cent styrene is used extensively in the ma­
    nufacture of tires and rubber goods. An other co-polymer of buta­
    diene and acrylonitrile is developed. This type of synthetic rub­
    ber is not .satisfactory for tires but its resistance to the solvent
    action of gasoline and oil finds many industrial applications.



  1. handy for erasing pencil marks - удобный для стирания каран­даша
  2. cross linkage - поперечные связи
  3. curing agents - вулканизирующие вещества


Answer the following questions:
  1. Where was rubber first discovered?
  2. Why did it get the name "rubber"?
  3. What are the properties of the natural rubber?
  4. What does vulcanization involve?
  5. What is more recent research of the rubber industry?
  6. What is the polimerization of isoprene?
  7. What was the first synthetic polymer developed?
  8. What are the main properties of Neoprene?
  9. What kind of synthetic rubber is used in the manufacture
    of tires?

10. What is the cost of Neoprene?


Вариант V

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Plastics


1. Viewed from the standpoint of organic chemistry it may be said that we are living in a "plastic age". So many articles formerly constructed of metal, wood, rubber, leather, or ceramics have been replaced by plastics. The use of plastic material in toys, swim­ming pools, home construction, automobiles, boats, airplanes and urticles of clothing has increased tremendously in the past few fears. The superior properties of many plastics have resulted in Ihe increased application of plastics in the electrical, radio, television, furniture, petroleum and food industries.

2 . Plastics are synthetic or natural materials which contain as an ential ingredient an organic substance of high molecule weight. They are solid in their finished state, but at some stages during manufacture or processing into finished articles they can be molded . Organic substances of high molecular weight are synthesized from relatively simple chemical components by condensation and polymerization reactions with synthetic resins. They are also pro­duced by chemical treatments of natural substances of high molecular weight, such as natural reaina, proteins and cellulose.

3 The modern plastic industry deals with moldable materials manu­red from organic compounds. A convenient classification of latics can be made on the basis of their behavior toward heat. Thermoplastics are permanently fusable, they melt or soften when ed and they harden when cooled. Thermoplastics are composed Line of molecules that is their atoms are joined in long chain-itructure with few cross linkage. Molecules of this type uaually swell or are soluble in some organic solvents.

4.Plastics are sometimes used without the addition of plaaticizers or fillers for the fabrication of commercial products, the being polyethilene film . However, they are usually modified by addition of fillers, dyes and pigments to give them the desired properties for specific uses and for processing.

5.Plasticis are synthetic polymers produced in the laboratory by ad reactions of various monomers. From a chemical standpoints polymers are divided into two main types, addition ро1уmers lonaation polymers.

6. Addition polymers are produced by the combination of monomers ■ double bond. Examples of such polymers are rubber, various synthetic rubbers and the vinyl type polymers. Co-polymerisation also produced a type of addition polymer by the combination of two or more different monomers.

7. Condengation polymers are formed by a chemical reaction bet­ween monomers that contain at least two reactive groups. The mono­mer units can thus react with other units to produce an unbroken chain of high molecular weight. Examples of condensation polymers are cellulose, nylon and the phenolformaldehyde type of plastics.
  1. Viewed from the standpoint of - рассматривая с точки зренкя
  2. mold - отливать форму
  3. plasticizers or fillers - пластификаторы или наполнители
  4. polyethilene film - полиэтиленовая пленка

Answer the following questions:

  1. Where do we use plastics?
  2. What does plastic аз essential ingredient contain?
  3. How are organic substances produced?
  4. What is a convenient classification of plastics?
  5. What are thermoplastics composed of?
  6. What process are synthetic polymers produced by in the laboratory?
  1. What types are polymers divided into?
  2. What examples of addition polymers do you know?
  3. What are condensation polymers formed by?

10. What condensation polymers do you know?


Контрольное задание * 4

для студентов специальности "Проектирование и технология трикотажных изделий"

Вариант I

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Spinning


I. Before fibres or filaments can be used in the making of cloth they must be converted into yarns. The process is called spinning.

2. Spinning is really a twisting of the fibres round each other so that they hold together and form a strong compact yarn. Not only the natural fibres, but also the chemical ones are to undergo a number of operations as they require to be doubled (i.e. several filaments have to be joined together) and twisted to give a strong yarn of suitable thickness for the fabric into which they are to be made.

The three necessary steps in spinning are: drawing out or "attenuating" the fibres, twisting them and winding the finished /urn on a bobbin.

3. The term "yarn" is applied to a twisted strand of fibres that in used in making woven or knitted cloth. It may consist of a single strand or of two or more strands twisted together.

4. Yarn should not be confused with thread. Thread is made by combining several yarns and twisting them together into one. Besides,the thread is given a smooth finish. Thread is usually stronger, smoother, and more uniform in diameter than yarn. Thread is used for sewing both at home and in clothing and footwear trades, yarn being used in the construction of fabrics either by weaving or by knitting.

5.A considerable amount of preparation is necessary before a yarn can be done from raw materials.

6. In their raw state the natural fibres are quite unsuitable for immediate conversion into yarn and they can be spun only after a number of preparatory operations. Cotton when it is picked still is seeds adhering to the fibres, flax is found as the inner bark of the stem of the flax plant, wool as a matted greasy mass of crimpy hairs, and they all contain impurities. These impurities should be removed, the fibres should be thoroughly cleaned plnced in a somewhat parallel position before spinning can take place.

7.As to silk, it has to be wound off the hardened cocoon, and
boiled off to become a silk filament.

8.The only fibres which in their raw state are practically ready
for the weaver's loom are the chemical fibres, which are made in
a continuous filament or thread. Even these are frequently cut
into short staples of equal length and spun in a similsr fashion
to the natural fibres.