丙烯酸酯乳液医用压敏胶的研究进展

综述了乳液型丙烯酸酯类医用压敏胶的性能特点以及各种改性方式的研究进展。通过加入增粘树脂、有机硅改性,采用反应性乳化剂、核／壳乳液聚合或接枝改性等方法提高其粘接强度,改善耐水性、耐温性及涂布性能,并对其应用前景进行了展望.     

Acrylic emulsion pressure-sensitive adhesives (PSAS) reinforced with layered silicate

Composite acrylic pressure-sensitive adhesives (PSAs) were synthesized by emulsion polymerization in the presence of montmorillonite (MMT). An examination with X-ray diffraction (XRD) and transmission electron microscopy (TEM) showed that both intercalated and exfoliated structures of MMT coexisted in the composites. It was demonstrated by X-ray photoelectron spectroscopy (XPS) that enrichment of the surface by the surfactant during drying of emulsion PSAs was depressed by the layered silicate. Significant improvements in storage modulus and cohesive strength were achieved by incorporation of MMT. The addition of only a small amount of MMT was enough to improve the adhesion properties of acrylic emulsion PSAs.     

分子质量调节剂对丙烯酸酯乳液压敏胶性能的影响

采用预乳化半连续聚合法,合成了丙烯酸酯乳液压敏胶。探讨了叔十二烷基硫醇、2,4-二苯基-4-甲基-1-戊烯、乙二醇以及异丙醇等分子质量调节剂对压敏胶聚合稳定性、黏度、初粘性、持粘性和180o剥离强度的影响。结果表明,叔十二烷基硫醇和异丙醇对压敏胶的性能影响较大,2,4-二苯基-4-甲基-1-戊烯和乙二醇的影响较小;随分子质量调节剂用量增大,压敏胶的初粘性增大,持粘性和180o剥离强度先增大后降低,黏度先降低后又增大;加入2,4-二苯基-4-甲基-1-戊烯和异丙醇的乳液压敏胶聚合稳定性随分子质量调节剂用量增大而变差,加入叔十二硫醇的乳液压敏胶的聚合稳定性则随用量增大先变差后又增强,而乙二醇则与之相反。     

Studies on the water resistance of acrylic emulsion pressure-sensitive adhesives (PSAs)

Four different types of acrylic emulsion pressure-sensitive adhesives (PSAs) with the same composition of their constituent co-polymers but stabilized by four different anionic surfactants, two conventional low-molecular-weight surfactants (a sodium salt and an ammonium salt) and two anionic monomers (a sodium salt and an ammonium salt) were prepared. The adhesion properties of the four types of PSA tapes coated onto PET (poly(ethylene terephthalate)) sheets were determined with the national standard methods of China. Water absorption and water solubility of PSA films were determined by the gravimetric method. The peel-strength retention of PSA tapes after immersion in water was compared. The results showed that both the adhesion properties and the water resistance of the acrylic PSAs stabilized by anionic monomers were better than that of the acrylic PSAs stabilized by low-molecular-weight surfactants, and the ammonium surfactants were better than the sodium surfactants. These differences were mainly caused by the different migration ability of the four surfactants in the PSA layers and their different hydrophilic nature, as explained in terms of surfactant content at the surfaces of PSA layers with X-ray photoelectron spectroscopy (XPS).     

Preparation of pressure-sensitive adhesives for the production of sticky foam at ambient temperature

In this paper, formulations for producing thermoplastic sticky foam, useful in preventing, delaying, or impeding access to protected materials or areas for military or law enforcement purpose, were investigated. Various formulations of pressure-sensitive adhesives (PSAs) using different amounts of thermoplastic elastomers (isoprene or Kraton D), tackifying agent (petroleum resin), chlorinated paraffin and silicone surfactant were prepared in toluene at ambient temperature. After vacuum stripping the solvent, the stability of the formulations and their tack properties (by tensile and hold tests) were determined. Combinations of the optimized formulations with different foaming agents were studied and compared concerning the expansion ratio and the stability of the foam (t_1/2 life time). A thermoplastic sticky foam with a density of 20 kg/m³ and a foam stability of 30 min (t_1/2) can be obtained by mixing two foaming agents (CHClF₂ and CO₂) with the optimized composition (comprising 60 parts of isoperene, 40 parts of petroleum resin, 50 parts of silicone surfactant and 250 parts of chlorinated paraffin (formulation no. 8)) in a pressurized vessel and releasing the contents to atmospheric pressure.     

UV-crosslinkable acrylic pressure-sensitive adhesives for industrial application

The focus of the development of UV-crosslinkable self-adhesive medical products is on one hand directed toward customer-oriented requirements such as tack, adhesion, cohesion, biocompatibility, and permeability for water vapor or air. The customer wants highly tolerable, breathable products, which are also characterized by very good skin and optimal release. On the other hand, the economic targets of medical products manufactures must be considered. Development in the area of UV-crosslinkable acrylic pressure-sensitive adhesives (PSA) for medical application describes the variety of acrylic composition, residue monomers content, quality control of peel adhesion level and repeating during the time, biocompatibility of the acrylic self-adhesive layers and their practical medical application. The new class of unsaturable copolymerizable photoinitiator, such as 4-acryloyloxy benzophenone was used for the synthesis of photoreactive UV-crosslinkable solvent-borne acrylic PSA. The properties of acrylic PSA were determined as well.     

室温下制备粘性泡沫用压敏胶粘剂

热塑性粘性泡沫材料可以用于防止、延迟或阻止外界物质进入用于军事或执法目的的受保护的材料或区域。本文通过对热塑性粘性泡沫材料的配方设计,采用不同量的热塑性弹性体（异戊二烯或Kraton D）、胶粘剂（石油树脂）、氯化石蜡和有机硅表面活性剂,以甲苯为溶剂,在室温下制备了不同配比的压敏胶粘剂（PSA）。真空抽取溶剂后,测试了配方的稳定性和粘接性能。将不同的发泡剂与最佳配方进行混合,研究和比较了粘性泡沫的膨胀倍率和泡沫稳定性（t1／2）。将2种发泡剂（CHClF2和CO2）与最佳配方组成物（由60份异戊二烯、40份石油树脂、50份有机硅表面活性剂、250份氯化石蜡组成）在压力容器中进行混合,然后减压至常压得到一种密度为20kg／m^3、泡沫稳定性为30min（t1／2）的热塑性粘性泡沫材料。     

聚合工艺对丙烯酸酯乳液胶粘剂性能的影响

主要研究了聚合工艺对丙烯酸酯乳液胶粘剂性能的影响 通过对乳液胶粘剂的各种性能测试,发现3种聚合方法中,种子乳液聚合法制备的乳液胶粘剂的综合性能较为理想 采用种子乳液聚合法,最佳聚合工艺为:单体的滴加时间4h、聚合温度50℃、搅拌速率80 r/min     

Miniemulsion and conventional emulsion copolymerization of styrene and butadiene: A comparative kinetic study

The kinetics of conventional and miniemulsion copolymerizations of styrene and butadiene were compared using the Mettler RC1 calorimeter. A two‐step homogenization procedure was applied to obtain miniemulsions of these monomers with hexadecane as the costabilizer. The results indicated that the miniemulsion polymerizations proceeded mainly by nucleation in the monomer droplets, while in the conventional emulsion polymerizations, particle formation occurred by a combination of micellar and homogeneous nucleation. The overall rate of miniemulsion polymerization was faster than the corresponding conventional emulsion system if the surfactant concentration was below the critical micelle concentration (cmc) and slower if the surfactant concentration was above the cmc. The homogenization process is important for making stable miniemulsion systems, but had no effect on the conventional emulsion system (without hexadecane), most likely because of the second stage addition of the butadiene monomer. The dependencies of the rate of polymerization (heat of reaction) and number of particles on the surfactant concentration differed for the two types of polymerization systems. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2304–2312, 2006     

Effect of organoclay and chain-transfer agent on molecular parameters and adhesion performance of emulsion pressure-sensitive adhesives

Organoclay-reinforced pressure-sensitive adhesives (PSAs) based on poly(butyl acrylate-co-vinyl acetate-co-acrylic acid) were prepared in the presence of an organically modified montmorillonite, that is, Cloisite15A (C15A), via in situ batch emulsion polymerization. The effect of C15A and chain transfer agent (CTA) level on the molecular parameters and adhesion properties of resulting reinforced PSA were investigated. Small-angle X-ray scattering (SAXS), gel permeation chromatography (GPC), transmission electron microscopy (TEM), dynamic mechanical thermal analysis (DMTA), and differential scanning calorimetry (DSC) were used to determine the characteristics of the neat and reinforced PSAs. The adhesion test results showed that the incorporation of C15A up to 1 wt% considerably increased the peel strength, shear and probe tack due to increasing the entanglement density of the PSA copolymer, while further increase lowered the peal and tack properties. Interestingly, the addition of 0.25 wt% CTA in the presence of 1 wt% C15A silicate layers resulted in PSA nanocomposite with the highest peal strength and probe tack. Although the CTA remarkably decreased the shear resistance of the neat PSA, the existence of C15A layers or tactoids in the reinforced PSAs decreased the rate of shear resistance decay due to the good interaction between the C15A and adhesive copolymer chains.     

Carboxymethylated polysaccharide-based films as carriers for acrylic pressure-sensitive adhesives

A novel application of a biodegradable polysaccharide-based film as a pressure-sensitive acrylic adhesive carrier has been reported. For film preparation carboxymethyl derivatives of starch (CMS) and cellulose (CMC) have been used. Based on physicochemical tests results (solubility in water, moisture absorption, mechanical properties) the most promising CMS/CMC 50/50 wt% film was selected as a carrier for an acrylic pressure-sensitive adhesive tape. Prepared double-sided self-adhesive tapes were characterized by good tack 5 N/2.5 cm, peel adhesion 12 N/2.5 cm and shear strength 90 N/6.25 cm² at 20 °C. Such acrylic self-adhesive tapes could find application in the paper industry.     

Solvent-based pressure-sensitive adhesives for PVC sign and marking films

This article shows the influence of parameters such as acrylic acid, initiator content, molecular mass, viscosity, content of methyl acrylate, content of ethyl acrylate, and content of N-vinyl caprolactam on such important parameters of pressure-sensitive adhesives as shrinkage, plasticity, adhesion to the steel, and deformation. Pressure-sensitive adhesives based on acrylic polymers and containing 2-ethylhexyl acrylate, methyl acrylate, acrylic acid, and N-vinyl caprolactam are used for production of self-adhesives containing polyvinyl chloride carrier. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 3212–3219, 2001     

Multifunctional propyleneimines-new generation of crosslinkers for solvent-based pressure-sensitive adhesives

This article describes work with the goal of crosslinking pressure sensitive acrylic adhesives (PSA) and a new generation of crosslinkers based on multifunctional propyleneimine derivates. Crosslinking of PSA is an established technology used in many industrial manufacturing processes. New applications and technical specifications stimulate the continuous development of new crosslinking agents with very interesting properties. These new crosslinkers influence physico-mechanical properties of acrylic PSA such as tack, peel resistance (adhesion) and shear strength (cohesion). The weak point of propyleneimine crosslinkers is their very short potlife.     

Characterization of pressure-sensitive adhesives. II. Water vapor permeation studies

The permeability of water vapor in a composite film [a Mylar (trademark of DuPont, Inc.) film coated with a pressure sensitive adhesive on both sides] and a Mylar film (type D) have been determined at 23°C. The water vapor permeability in the pressure sensitive adhesive, Flexbond 150 (a trademark of Air Products and Chemicals), and the Mylar film have been found to be 3.23 × 10^?7 and 2.30 × 10^?8 cm³ (STP) cm · cm^?2 · s^?1 · (cm Hg)^?1, respectively, at 23°C.     

Mechanism for the action of tackifying resins in pressure-sensitive adhesives

In a study of pressure-sensitive adhesives prepared from mixtures of natural rubber and three different tackifying resins, it was shown that a tackifying resin may form either one- or two-phase systems with natural rubber. Measurements of the viscoelastic properties of the adhesives show that the effect of tackifying resins is to modify the viscoelastic properties so that the adhesive performance in bonding and unbonding is improved. It is suggested that a two-phase system is not necessary for good tack, and a theory based on a two-phase system cannot adequately explain the rate dependence of tack tests. Tack measured by the probe test is shown to be dependent upon a balance between the viscoelastic properties and the transition temperature of the adhesives. This theory is used to explain the effect of contact time, withdrawal speed, and resin softening point on the tack of adhesives.     

SISO-based hot-melt pressure-sensitive adhesives for transdermal delivery of hydrophilic drugs

A monomer-activated anionic polymerization approach was utilized to synthesize poly(styrene-b-isoprene-b-styrene-b-ethylene oxide) tetrablock terpolymers (SISO), which were melt-mixed with tackifiers and plasticizer to develop polar SISO-based hot-melt pressure-sensitive adhesives (HMPSAs) for transdermal delivery of hydrophilic drugs. Their hydrophilic performance was characterized using contact angle analysis. Their adhesive performances were measured in terms of 180° peel strength and holding power. In vitro drug release experiments were carried out using a modified Franz type horizontal diffusion cell, in which geniposide was chosen as a hydrophilic model drug. The results show that poly(ethylene oxide) (PEG) blocks exhibit substantial effects on adhesive performance and the release behavior of the model drug. The shorter PEG molecular chains enhance adhesive performance and the cumulative release rate of the model drug in the SISO-based HMPSAs. The longer PEG molecular chains tend to crystallize. Their crystallization structures have negative effects on adhesive performance and limit the dissolution and diffusion of drugs in the SISO-based HMPSAs. Therefore, appropriate PEG molecular chains are required to fabricate SISO-based HMPSAs with excellent adhesive performance for transdermal delivery of hydrophilic drugs.     

Miniemulsion and conventional emulsion copolymerization of styrene and butadiene: Effect of process on gel content

The properties of styrene/butadiene copolymers obtained by conventional emulsion and miniemulsion polymerizations were studied. Thin layer chromatography with flame ionization detection was used to determine the gel fraction of the copolymer in the latex particles as a function of conversion. It was found that the gel formation began at a higher conversion in the miniemulsion polymerization when compared with that in the conventional process. Also, a lower glass transition temperature was noted at the lowest conversion sampled (～25%), implying a higher initial butadiene monomer concentration within the nucleated miniemulsion monomer droplets when compared with particles formed conventionally. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4616–4622, 2006     

保护膜用有机硅改性丙烯酸酯乳液压敏胶的研究

以八甲基环四硅氧垸（D1）、γ-甲基丙烯酰氧基丙基三乙氧基硅烷（KH-570）、六甲基二硅氧烷（MM）为主要原料,Me4NOH为催化剂和二甲基亚砜（DMSO）为促进剂,通过本体聚合合成了有机硅大分子。用该有机硅大分子和丙烯酸酯进行乳液共聚制得了有机硅改性丙烯酸酯乳液压敏胶,该压敏胶涂在PE膜上制成的保护膜贴在被保护表面能有效地抑制剥离强度的增长.     

表面保护胶带用聚丙烯酸酯乳液压敏胶的研究

用半连续预乳化种子乳液聚合法合成了保护膜用乳液压敏胶,主要研究了底相种子乳液中乳化剂的用量、多官能度氮丙啶类交联剂的用量对乳液压敏胶性能的影响。研究结果表明:随着种子乳液中乳化剂用量的增加,乳胶粒的粒径减小,乳液粘度、表面张力和接触角增加;增加交联剂的用量可显著提高乳液压敏胶的耐老化性能;同温度相比,湿度对乳液压敏胶的耐老化性能影响更加显著;被保护材料表面的极性和光洁度对压敏胶的耐老化性能亦有显著影响。     

绷带用聚丙烯酸酯乳液型压敏胶的研制

合成了一种绷带用聚丙烯酸酯乳液型压敏胶,测试了乳液的粘度、压敏胶的T型剥离强度、初粘力及持粘力。结果表明:当反应温度为81～85℃、引发剂用量为0．35%～0．45%、复配乳化剂用量为3．8%时,制得的聚丙烯酸酯乳液性能较好;加入一定量的松香乳液,可有效地提高压敏胶的性能。