Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – Specific organic component
Reexamination Certificate
2001-04-27
2003-06-10
Hardee, John (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
Specific organic component
C510S327000
Reexamination Certificate
active
06576606
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is directed to organopolysiloxane compositions useful as softeners for textile products, to a process for softening textile products with such compositions, and to the products thus treated.
2. Background Art
Textile “finishes” represent a large commercial market. Many types of such finishes are available, and are formulated with specific reference to their end use. For example, many fiber lubricant compositions are available which lower the coefficient of friction of fibers during processing. Other textile finishes are applied to yarns and woven textiles to make these products water repellent, while still further compositions are added to wovens and non-wovens to impart increased strength characteristics. The present application is not directed to finishes generally, but to a particular class of finishes known as “softeners”.
Softeners are applied to textile products such as fibers, yarn, wovens or non-wovens, to impart a soft feel, or “hand”. This increased softness is readily perceptible to the ultimate consumer, and thus softeners represent important items of commerce. To be commercially acceptable, softeners must exhibit several important characteristics following application to a textile substrate. The textile will desirably possess a soft hand; the textile must be readily wettable; and the softener must not cause yellowing of the product.
The above characteristics are often conflicting, and it is difficult to obtain all these properties in a given softener composition. For example, organopolysiloxane fluids such as polydimethylsiloxanes (“PDMS fluids”) are known to provide some improvement in softness. However, these products must be emulsified with considerable quantities of surfactants, which leave a residue which can cause undesirable changes in color. Use of organic solvents such as white oils in lieu of water allows elimination of surfactants. Use of organic solvents is not desirable, however. Moreover, the treated fabrics tend to be hydrophobic, with long wetting times, and only modest improvement of hand is achieved.
In U.S. Pat. No. 4,247,592 it is proposed to employ aminoalkyl-functional polyorganosiloxanes as fabric softeners. Such products require somewhat less emulsifier, and can produce an outstanding pleasing, soft hand. However, fabrics treated with compositions containing aminofunctional PDMS fluids are prone to yellowing over time, believed to be caused by oxidation of the aminoalkyl groups by atmospheric oxygen or ozone. A variety of proposals have been made to eliminate the yellowing problem. However, the majority of these either result in only modest improvement, or do so at greatly increased cost. Modest improvement in yellowing at some sacrifice of hand is disclosed by U.S. Pat. No. 4,978,363, wherein fatty acid salts of amimoalkyl-substituted organopolysiloxane are employed.
Softeners have been proposed where piperidinyl or morpholinyl moieties have been substituted for the readily available aminoalkyl functionality. An example is U.S. Pat. No. 5,540,952. However, the synthesis of such compounds tends to be difficult and expensive.
U.S. Pat. No. 4,507,455 discloses softeners prepared by N-acylation of organopolysiloxanes with pendant aminoalkyleneaminoalkyl groups. While these acylated softeners show improvements in yellowing behavior, their softening characteristics are not ideal. Indeed, in U.S. Pat. No. 4,978,561 and commonly assigned U.S. Pat. No. 5,100,991, it is stated that such acylated amino-functional silicone fluids do not provide a particularly soft hand, but rather impart a harsh feel. The '561 and '991 patents disclose acylation of pendant aminoalkyl and polyaminopolyalkylene organopolysiloxanes with lactones to produce N-(hydroxyalkyl)acylated products.
Neat N-acylated amino-functional silicones and silanes have been disclosed as being useful for coupling agents in fiber reinforced composites. In such applications, as typified by U.S. Pat. Nos. 2,929,829 and 3,440,261, neat silicone or silicone dissolved in volatile organic solvent is applied to glass fiber or carbon fiber reinforcement, glass microballoons, etc., prior to impregnating with thermosetting resin. The cured composites are said to exhibit greater strength characteristics due to increased adhesion between reinforcement and polymer matrix.
In U.S. Pat. No. 5,302,659 is disclosed a novel method of preparing N-acylated, aminoalkyl-functional organopolysiloxanes useful as softeners. In this process, organopolysiloxanes having hydroxyl-(silanol) or alkoxy-functional end groups and pendant aminoalkyl groups are reacted with an acyclic carboxylic acid anhydride or a cyclic dicarboxylic acid anhydride to form, in the former case, an N-acylated product having an
acyl group where R is alkyl, or in the latter case, a
group where R is alkylene or alkenylene. The N-acylation takes place in the dispersed phase, but requires a large amount of anhydride. Moreover, the products exhibit only modest improvement in hand over untreated textile, and a longer than desired wetting time.
It would be desirable to provide a softener composition which provides excellent softening, which is readily wettable, and which resists yellowing. Such a softener should also be manufacturable at a cost which is commercially viable.
SUMMARY OF THE INVENTION
The present invention pertains to softeners based on acylated aminoalkyl-functional organopolysiloxanes which are readily emulsifiable, and which produce fabrics with soft hand, rapid wettability, and high yellowing resistance. The softeners are amides formed by acylating &agr;,&ohgr;-aminoalkyl-functional organopolysiloxane fluids.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The subject invention softeners are prepared by N-acylating (hereinafter, “acylating”) &agr;,&ohgr;-aminoalkyl-functional organopolysiloxane fluids. The degree of acylation may vary, but is preferably at least 50 mol percent based on moles of primary and/or secondary amino groups present, more preferably at least 75 mol percent, and yet more preferably 90 mol percent or more. Most preferably, all amino groups are acylated. The acylation produces amide groups, and may, in addition, produce a limited, minor amount of imide groups in certain instances. Imide groups are preferably absent.
The &agr;,&ohgr;-aminoalkyl-functional organopolysiloxanes are preferably of the formula
XR
2
SiO—(XRSiO)
m
—(R
2
SiO)
n
—SiR
2
X
where X is an aminoalkyl group as defined hereafter, R is a hydrocarbon(oxy) group, and n and m are such that the fluid has a neat viscosity at room temperature from 1 cP to 100,000 cP. In the above formula, and in the claims, it does not depart from the spirit of the invention to include a minor quantity of RSiO
3/2
, XSiO
3/2
, or SiO
4/2
moieties, so long as the product is substantially linear, i.e., remains a liquid at room temperature. The organopolysiloxane may also contain interspersed linking groups, preferably alkylene groups such as ethylene, hexylene, etc., or polyoxyalkylene residues bonded to Si either at an oxygen, or preferably at carbon of the polyoxyalkylene moiety.
In the above formula, R is preferably a C
1-20
alkyl group, more preferably a C
1-8
alkyl group or phenyl group, yet more preferably a methyl, ethyl, or phenyl group, and most preferably, methyl. In some formulations, some R may be alkoxy, preferably C
1-8
alkoxy, more preferably C
1-4
alkoxy, and most preferably methoxy or ethoxy, hydroxyl (—OH), substituted alkyl, e.g., haloalkyl, preferably chloroalkyl or fluoroalkyl. The nature of the various R groups is not overly critical, provided the advantageous properties of the softener are not affected thereby. A limited number of R may be polyoxyalkylene, i.e., pendant as opposed to “in chain” polyoxyalkylene groups.
Examples of preferred amino-functional radicals “X” are radicals of the general formula (II)
—R
1
—[NR
2
(CH
2
)
a
]
b
NHR
2
(II)
and ammonium salts thereof which can be prepared by reaction with mineral or carboxylic acid
Helvey Jesse E.
Richards, III John H.
Brooks & Kushman P.C.
Hardee John
Kelmar Industries, Inc.
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