Task 4 To describe the properties of various types ofmanmade fibers描述化学纤维

General information 1 Manmade fibers化学纤维

The three major spinning，or extrusion，processes are wet spinning，dry or solvent spinning，and melt spinning（Fig.1.17）.A fourth type，emulsion spinning，can be used for polymers for which the other processes are not practical.Gel spinning is a new process that is being used for a few high-tenacity fibers.

The shape of the spinnerette and the method of spinning influence the cross-sectional shape of a fiber.Most spinnerettes are common round openings.Other shapes are available to produce fibers with special characteristics.

After fibers are extruded，they are usually stretched，or drawn，to improve the orientation of the polymer chains.The amount the fiber is stretched is reported as the draw ratio：the ratio of the length of the fiber when stretched to its length when unstretched.Draw ratios of 1 or 2 are common for rayon.Ratios of 4 or 6 are not uncommon for other fibers.In some cases，drawing may occur in more than one stage.Some fibers are sold as undrawn or partially drawn yarns.

New Words and Expressions

dissatisfaction不满意

considerable相当多的

stock原料

continuity继续，连续

upheaval动荡，动乱

spur刺激，激发

substitute代替物，替代品

ensure确保，保证

competitive竞争性的

durable耐用的，持久的

synthesized合成的，综合的

regenerated再生的

conversion转变

nozzle喷嘴，喷管

spinnerette喷丝板，吐丝管

slender细长的，苗条的

stretch拉直，拉长

draw 牵伸

emulsion spinning乳液纺丝

gel spinning凝胶纺丝

cross-sectional横截面的

round圆的

orientation定向，倾向性

draw ratio拉伸比

texture变形

Notes

1.such concerns spur the development of manufactured substitutes for natural fibers to ensure a continuous fiber supply at a competitive price.

这种关注刺激了天然纤维替代品的发展，确保纤维在竞争性的价格下得到持续供应。

2.forming a long slender filament；stretching or drawing the material；and collecting the fiber for further processing or sale.

形成一根细长的长丝，再经过牵伸；然后把纤维并合起来进行下一步的加工或出售。

3.The three major spinning，or extrusion，processes are wet spinning，dry or solvent spinning，and melt spinning.

三种主要的纺丝过程是湿法纺丝、干法纺丝和熔融纺丝。

4.the orientation of the polymer chains.

高分子链的取向性。

Exercises

Part 1 Put the following expressions into Chinese

1.Fibers must be given special finishes to produce desirable properties for consumers.

2.Whether a fiber-forming polymer is chemically synthesized or regenerated from a naturally occurring polymer…

3.The specific process used depends on the type of polymer being extruded.

4.Gel spinning is a new process that is being used for a few high tenacity fibers.

5.Other shapes are available to produce fibers with special characteristics.

Part 2 Questions

1.How should fiber be processed from the manufacturer’s point of view?

2.How about the nature fiber from consumer’s point of view?

3.What are several spinning processes?

Unit 1 Viscose黏胶纤维

Viscose is a type of rayon.It was the first manufactured fiber.Unlike most man-made fibers，it’s not a synthetic fibers，it’s a man-made fiber made from purified cellulose，which usually comes from specially processed wood pulp.As a result，viscose rayon has a silky appearance and feel，and also has the ability to breathe in a manner similar to cotton weaves.In addition to being an inexpensive material to use in lightweight clothing，viscose can also be used for such textiles as tablecloths，napkins，furniture slipcovers，and sheeting.One of the more popular properties of viscose rayon is that the fabric tends to drape very well，which makes it ideal for use in simple curtains，as well as the perfect fabric to line more formal draperies.

The fiber has a serrated round shape with a smooth surface.The fiber morphology is shown in Fig.1.18.

Viscose Rayon Properties：

Viscose rayon is a medium-weight fiber with fair to good strength and abrasion resistance.It is hydrophilic（11%moisture regain）.

The fiber is washable under proper care conditions and is dry cleanable.There are no static or pilling problems.

Viscose rayon loses 30%～50%of its strength when wet，thus requiring great caution in laundering.It recovers strength when dry.It has very poor elasticity and resiliency.It also shrinks appreciably from washing.

Viscose fiber swell in water.This causes the fabric to shrink.Swelling and shrinkage can be reduced by treatment with synthetic resins.The treatment also improves wrinkle recovery but moisture absorbency is reduced.

New Words and Expressions

viscose黏胶纤维

rayon人造（纤维素）纤维，人造丝

manufactured制成的，人造的

man-made fiber化学纤维

wood pulp木浆

serrated锯齿状的，有锯齿的

abrasion resistance耐磨牢度，抗磨损性

hydrophilic亲水性的

appearance外观

tablecloth桌布

napkin手帕，餐巾

slipcover覆盖物，家具套

sheeting床单，被单布

curtain窗帘，幕布

pilling起球

shrink收缩，缩水

drape悬垂性，褶裥

synthetic resin 合成树脂

Unit 2 Acetate醋酯纤维

Acetate is not a strong fiber but can be extruded into fibers of different diameter and woven into fabrics that have the luxurious look of silk but do not wear like silk.Acetate does not absorb moisture readily but dries fast and resists shrinking.This is a resilient fabric that resists wrinkling in addition to being pliable and soft with a good drape.Triacetate is an improved acetate fabric which doesn’t melt easily and is easy to care for.

The spinning solution of acetate filament is made by dissolving cellulose acetate in acetone containing a small amount of water（up to 10 percent）.The solution is filtered and pumped through the fine holes of a spinneret.As the jets of cellulose acetate solution emerge they meet a stream of warm air which evaporates the acetone，leaving the solid cellulose acetate in the form of fine filaments.

Acetate staple is now produced by cutting the continuous filaments into short lengths.The staple length is chosen to blend suitably with other fibers in making mixed yarns.

Filament yarn may be twisted to the level of consumer requirements and packaged on paper cones.One trend is the development of packages which will deliver a zero twist yarn，and the utilization of the yarn is at low twist levels.

New Words and Expressions

acetate fiber 醋酯纤维

triacetate三醋酯纤维

nail polish 指甲油

alcohol 酒精，乙醇

super glue超强力胶水

acetone 丙酮

cone 锥形筒子

zero twist yarn 无捻纱

pliable柔韧的

Notes

1.up to 10 percent：最高达10%，含有可少于10%的意思。

2.The solution is filtered and pumped through the fine holes of a spinneret.

纺丝液经过滤后，借助于泵的压力穿过喷丝头的细孔。

3.As the jets of cellulose acetate solution emerge they meet a stream of warm air which evaporates the acetone，leaving the solid cellulose acetate in the form of fine filaments.

在醋酯纤维素的射流束出现时，会遇到一股热气流，丙酮被蒸发，剩下的则是细丝状的醋酯纤维素。

4.One trend is the development of packages which will deliver a zero twist yarn，and the utilization of the yarn is at low twist levels.

目前的一种趋势是使用的筒子在退绕时不给纱线加捻，这样纱线在使用时可以保持较低的捻度。

Questions

1.How is the acetate filament produced?

2.What are the main considerations when cutting the filament into staple fibers?

Unit 3 Rayon人造丝

Rayon，from cellulose，has many of the qualities of cotton，a natural cellulose fiber.Rayon is strong，extremely absorbent，comes in a variety of qualities and weights，and can be made to resemble natural fabrics.Rayon does not melt but burns at high temperatures.Rayon drapes well.It has a soft，silky hand，and a smooth，napped，or bulky surface.Rayon will wrinkle easily and may stretch when wet and shrink when washed.

New Words and Expressions

bulky 颗粒状的

napped 绒毛的

resemble 类似

Unit 4 Lyocell（Tencel）莱赛尔（天丝）

Tencel®（Fig.1.19）is the registered trade name for Lyocell.Tencel（Lyocell）is the first new fiber in 30 years，and being made of wood pulp cellulose，it is the first new natural fiber in a lot longer than that.The properties and production processes were unique enough for the US Federal Trade Commission to designate Tencel as a separate fiber group.Tencel was developed by Tencel Inc.，and Tencel is the registered trademark of Tencel Ltd.

The raw material for Lyocell manufacture is cellulose derived from wood，the manufacture process is short and fast，and is environmentally friendly.The solvent is almost all recovered and the waste is harmless.

Lyocell has good dry and wet strength—usually better than other man-made cellulosic fibers.The dry strength is better than middle grade cotton.Wet strength is lower than the dry strength.The extensibility of staple fibers，at 10%to 14%，is somewhat higher than that of cotton.Elasticity is low，as with all cellulosic fibers.

Fiber fineness can be similar to cotton or wool，ranging from 1.1～3.3dtex.

Clothing comfort properties are comparable to other cellulosic fibers.Moisture absorption is less than viscose but greater than cotton.

A peach-skin finish can be obtained by emerising.Other typical process are raising and shrinking.

New Words and Expressions

extensibility 延伸性

moisture absorption 吸湿性

peach-skin finish 桃皮绒整理

emerise 磨毛

raise 起绒

shrink收缩

Unit 5 Modal莫代尔

ModalⓇ（Fig.1.20）is a trademarked fiberfrom an Austrian textilecompany，Lenzing.Modal is a fiber made fromspun beechwood cellulose.Characteristics are as follows.

1.Modal fabrics have softness handle，good drape and comfortable wearing.

2.Modal fabrics have good moisture regain and air permeability which is better than cotton fabrics，it is the ideal material of body suit and health suit，which can be done favor of physiology circulation and health of body.

3.Modal fabrics have level up surface，fine and smooth and velvet，which have the effect of natural silk.

4.Modal has a high dry strength and much high wet strength than viscose.

5.Breaking extension is 15%～30%—more than double that of cotton.

New Words and Expressions

beechwood山毛榉木材

moisture regain 回潮率

air permeability 透气性

physiology 生理学，生理机能

level up 平整的

velvet 天鹅绒（般的）

breaking extension 断裂伸长